diff --git a/schema/schema.definition.sql b/schema/schema.definition.sql
index 31087be..3e72a2f 100644
--- a/schema/schema.definition.sql
+++ b/schema/schema.definition.sql
@@ -994,32 +994,40 @@ CREATE FUNCTION maevsi.invitation_claim_array() RETURNS uuid[]
     LANGUAGE plpgsql STABLE STRICT
     AS $$
 DECLARE
-  _arr UUID[];
-  _result_arr UUID[] := ARRAY[]::UUID[];
-  _id UUID;
+  _invitation_ids UUID[];
+  _invitation_ids_unblocked UUID[] := ARRAY[]::UUID[];
+  _invitation_id UUID;
 BEGIN
-  _arr := string_to_array(replace(btrim(current_setting('jwt.claims.invitations', true), '[]'), '"', ''), ',')::UUID[];
-  FOREACH _id IN ARRAY arr
-  LOOP
-    -- omit invitations authored by a blocked account
-   IF NOT EXISTS(
-	  SELECT 1
-	  FROM maevsi.invitation i
-	    JOIN maevsi.contact c ON i.contact_id = c.contact_id
-	    JOIN maevsi.account_block b ON c.author_account_id = b.blocked_account_id
-	  WHERE i.id = _id and b.author_account_id = current_setting('jwt.claims.account_id', true)
-	) THEN
-      _result_arr := append_array(result_arr, _id);
-	END IF;
-  END LOOP;
-
-  RETURN _result_arr;
+  _invitation_ids := string_to_array(replace(btrim(current_setting('jwt.claims.invitations', true), '[]'), '"', ''), ',')::UUID[];
+  IF _invitation_ids IS NOT NULL THEN
+    FOREACH _invitation_id IN ARRAY _invitation_ids
+    LOOP
+      -- omit invitations authored by a blocked account
+      IF NOT EXISTS(
+	      SELECT 1
+	      FROM maevsi.invitation i
+	      JOIN maevsi.contact c ON i.contact_id = c.contact_id
+	      JOIN maevsi.account_block b ON c.author_account_id = b.blocked_account_id
+	     WHERE i.id = _invitation_id and b.author_account_id = current_setting('jwt.claims.account_id', true)
+	    ) THEN
+        _invitation_ids_unblocked := append_invitation_array(result_invitation_ids, _invitation_id);
+	    END IF;
+    END LOOP;
+  END IF;
+  RETURN _invitation_ids_unblocked;
 END
 $$;
 
 
 ALTER FUNCTION maevsi.invitation_claim_array() OWNER TO postgres;
 
+--
+-- Name: FUNCTION invitation_claim_array(); Type: COMMENT; Schema: maevsi; Owner: postgres
+--
+
+COMMENT ON FUNCTION maevsi.invitation_claim_array() IS 'Returns the current invitation claims as UUID array.';
+
+
 --
 -- Name: invitation_contact_ids(); Type: FUNCTION; Schema: maevsi; Owner: postgres
 --
@@ -1029,17 +1037,25 @@ CREATE FUNCTION maevsi.invitation_contact_ids() RETURNS TABLE(contact_id uuid)
     AS $$
 BEGIN
   RETURN QUERY
-    SELECT invitation.contact_id FROM maevsi.invitation
-    WHERE id = ANY (maevsi.invitation_claim_array())
+    SELECT i.contact_id FROM maevsi.invitation i
+    WHERE i.id = ANY (maevsi.invitation_claim_array())
     OR (
-	   event_id IN (SELECT maevsi.events_organized())
-	   AND
-	   -- omit contacts authored by a blocked account or referring to a blocked account
-	   contact_id NOT IN (
-		 SELECT c.id
-		 FROM maevsi.contact c
-		   JOIN maevsi.account_block b ON c.author_account_id = b.blocked_account_id OR c.account_id = b.blocked_account_id
-		 WHERE b.author_account_id = NULLIF(current_setting('jwt.claims.account_id', true), '')::UUID
+	    i.event_id IN (SELECT maevsi.events_organized())
+	    AND
+	    -- omit contacts authored by a blocked account or referring to a blocked account
+	    i.contact_id NOT IN (
+        SELECT c.id
+        FROM maevsi.contact c
+        WHERE c.account_id IS NULL
+        OR c.account_id NOT IN (
+          SELECT blocked_account_id
+          FROM maevsi.account_block
+          WHERE author_account_id = NULLIF(current_setting('jwt.claims.account_id', true), '')::UUID
+          UNION ALL
+          SELECT author_account_id
+          FROM maevsi.account_block
+          WHERE blocked_account_id = NULLIF(current_setting('jwt.claims.account_id', true), '')::UUID
+        )
 	   )
 	);
 END;
@@ -1543,25 +1559,29 @@ BEGIN
   jwt_account_id := NULLIF(current_setting('jwt.claims.account_id', true), '')::UUID;
 
   RETURN QUERY
-  SELECT event_id FROM maevsi.invitation
+  SELECT i.event_id FROM maevsi.invitation i
   WHERE
     (
-      contact_id IN (
+      i.contact_id IN (
         SELECT id
         FROM maevsi.contact
         WHERE
           account_id = jwt_account_id
-		  -- The contact selection does not return rows where account_id "IS" null due to the equality comparison.
-		  AND
-		  -- contact not created by a blocked account
-		  author_account_id NOT IN (
-			SELECT account_block_id
-			FROM maevsi.account_block
-		    WHERE b.author_account_id = jwt_account_id
-		  )
-		)
+          -- The contact selection does not return rows where account_id "IS" null due to the equality comparison.
+          AND
+          -- contact is not a blocked user and is not authored by a user who blocked jwt_account_id
+          author_account_id NOT IN (
+            SELECT blocked_account_id
+            FROM maevsi.account_block
+            WHERE author_account_id = jwt_account_id
+            UNION ALL
+            SELECT author_account_id
+            FROM maevsi.account_block
+            WHERE blocked_account_id = jwt_account_id
+          )
+      )
     )
-    OR id = ANY (maevsi.invitation_claim_array());
+    OR i.id = ANY (maevsi.invitation_claim_array());
 END
 $$;
 
@@ -1657,7 +1677,7 @@ COMMENT ON COLUMN maevsi.account_block.blocked_account_id IS 'The id of the acco
 -- Name: COLUMN account_block.created_at; Type: COMMENT; Schema: maevsi; Owner: postgres
 --
 
-COMMENT ON COLUMN maevsi.account_block.created_at IS '@omit update,delete
+COMMENT ON COLUMN maevsi.account_block.created_at IS '@omit create,update,delete
 The timestamp when the blocking was created.';
 
 
@@ -3659,7 +3679,7 @@ CREATE POLICY account_block_insert ON maevsi.account_block FOR INSERT WITH CHECK
 -- Name: account_block account_block_select; Type: POLICY; Schema: maevsi; Owner: postgres
 --
 
-CREATE POLICY account_block_select ON maevsi.account_block FOR SELECT USING ((((NULLIF(current_setting('jwt.claims.account_id'::text, true), ''::text))::uuid IS NOT NULL) AND (author_account_id = (NULLIF(current_setting('jwt.claims.account_id'::text, true), ''::text))::uuid)));
+CREATE POLICY account_block_select ON maevsi.account_block FOR SELECT USING (((author_account_id = (NULLIF(current_setting('jwt.claims.account_id'::text, true), ''::text))::uuid) OR (blocked_account_id = (NULLIF(current_setting('jwt.claims.account_id'::text, true), ''::text))::uuid)));
 
 
 --
@@ -3710,9 +3730,17 @@ CREATE POLICY contact_insert ON maevsi.contact FOR INSERT WITH CHECK (((author_a
 
 CREATE POLICY contact_select ON maevsi.contact FOR SELECT USING ((((account_id = (NULLIF(current_setting('jwt.claims.account_id'::text, true), ''::text))::uuid) AND (NOT (author_account_id IN ( SELECT account_block.blocked_account_id
    FROM maevsi.account_block
-  WHERE (account_block.author_account_id = (NULLIF(current_setting('jwt.claims.account_id'::text, true), ''::text))::uuid))))) OR ((author_account_id = (NULLIF(current_setting('jwt.claims.account_id'::text, true), ''::text))::uuid) AND (NOT (account_id IN ( SELECT account_block.blocked_account_id
+  WHERE (account_block.author_account_id = (NULLIF(current_setting('jwt.claims.account_id'::text, true), ''::text))::uuid)
+UNION ALL
+ SELECT account_block.author_account_id
+   FROM maevsi.account_block
+  WHERE (account_block.blocked_account_id = (NULLIF(current_setting('jwt.claims.account_id'::text, true), ''::text))::uuid))))) OR ((author_account_id = (NULLIF(current_setting('jwt.claims.account_id'::text, true), ''::text))::uuid) AND ((account_id IS NULL) OR (NOT (account_id IN ( SELECT account_block.blocked_account_id
+   FROM maevsi.account_block
+  WHERE (account_block.author_account_id = (NULLIF(current_setting('jwt.claims.account_id'::text, true), ''::text))::uuid)
+UNION ALL
+ SELECT account_block.author_account_id
    FROM maevsi.account_block
-  WHERE (account_block.author_account_id = (NULLIF(current_setting('jwt.claims.account_id'::text, true), ''::text))::uuid))))) OR (id IN ( SELECT maevsi.invitation_contact_ids() AS invitation_contact_ids))));
+  WHERE (account_block.blocked_account_id = (NULLIF(current_setting('jwt.claims.account_id'::text, true), ''::text))::uuid)))))) OR (id IN ( SELECT maevsi.invitation_contact_ids() AS invitation_contact_ids))));
 
 
 --
@@ -3755,7 +3783,11 @@ CREATE POLICY event_insert ON maevsi.event FOR INSERT WITH CHECK ((((NULLIF(curr
 
 CREATE POLICY event_select ON maevsi.event FOR SELECT USING ((((visibility = 'public'::maevsi.event_visibility) AND ((invitee_count_maximum IS NULL) OR (invitee_count_maximum > maevsi.invitee_count(id))) AND (NOT (author_account_id IN ( SELECT account_block.blocked_account_id
    FROM maevsi.account_block
-  WHERE (account_block.author_account_id = (NULLIF(current_setting('jwt.claims.account_id'::text, true), ''::text))::uuid))))) OR (author_account_id = (NULLIF(current_setting('jwt.claims.account_id'::text, true), ''::text))::uuid) OR (id IN ( SELECT maevsi_private.events_invited() AS events_invited))));
+  WHERE (account_block.author_account_id = (NULLIF(current_setting('jwt.claims.account_id'::text, true), ''::text))::uuid)
+UNION ALL
+ SELECT account_block.author_account_id
+   FROM maevsi.account_block
+  WHERE (account_block.blocked_account_id = (NULLIF(current_setting('jwt.claims.account_id'::text, true), ''::text))::uuid))))) OR (author_account_id = (NULLIF(current_setting('jwt.claims.account_id'::text, true), ''::text))::uuid) OR (id IN ( SELECT maevsi_private.events_invited() AS events_invited))));
 
 
 --
@@ -3803,10 +3835,15 @@ EXCEPT
  SELECT c.id
    FROM (maevsi.contact c
      JOIN maevsi.account_block b ON (((c.account_id = b.author_account_id) AND (c.author_account_id = b.blocked_account_id))))
-  WHERE (c.account_id = (NULLIF(current_setting('jwt.claims.account_id'::text, true), ''::text))::uuid))) OR ((event_id IN ( SELECT maevsi.events_organized() AS events_organized)) AND (NOT (contact_id IN ( SELECT c.id
-   FROM (maevsi.contact c
-     JOIN maevsi.account_block b ON (((c.author_account_id = b.blocked_account_id) OR (c.account_id = b.blocked_account_id))))
-  WHERE (b.author_account_id = (NULLIF(current_setting('jwt.claims.account_id'::text, true), ''::text))::uuid)))))));
+  WHERE (c.account_id = (NULLIF(current_setting('jwt.claims.account_id'::text, true), ''::text))::uuid))) OR ((event_id IN ( SELECT maevsi.events_organized() AS events_organized)) AND (contact_id IN ( SELECT c.id
+   FROM maevsi.contact c
+  WHERE ((c.account_id IS NULL) OR (NOT (c.account_id IN ( SELECT account_block.blocked_account_id
+           FROM maevsi.account_block
+          WHERE (account_block.author_account_id = (NULLIF(current_setting('jwt.claims.account_id'::text, true), ''::text))::uuid)
+        UNION ALL
+         SELECT account_block.author_account_id
+           FROM maevsi.account_block
+          WHERE (account_block.blocked_account_id = (NULLIF(current_setting('jwt.claims.account_id'::text, true), ''::text))::uuid))))))))));
 
 
 --
@@ -3820,10 +3857,15 @@ EXCEPT
  SELECT c.id
    FROM (maevsi.contact c
      JOIN maevsi.account_block b ON (((c.account_id = b.author_account_id) AND (c.author_account_id = b.blocked_account_id))))
-  WHERE (c.account_id = (NULLIF(current_setting('jwt.claims.account_id'::text, true), ''::text))::uuid))) OR ((event_id IN ( SELECT maevsi.events_organized() AS events_organized)) AND (NOT (contact_id IN ( SELECT c.id
-   FROM (maevsi.contact c
-     JOIN maevsi.account_block b ON (((c.author_account_id = b.blocked_account_id) OR (c.account_id = b.blocked_account_id))))
-  WHERE (b.author_account_id = (NULLIF(current_setting('jwt.claims.account_id'::text, true), ''::text))::uuid)))))));
+  WHERE (c.account_id = (NULLIF(current_setting('jwt.claims.account_id'::text, true), ''::text))::uuid))) OR ((event_id IN ( SELECT maevsi.events_organized() AS events_organized)) AND (contact_id IN ( SELECT c.id
+   FROM maevsi.contact c
+  WHERE ((c.account_id IS NULL) OR (NOT (c.account_id IN ( SELECT account_block.blocked_account_id
+           FROM maevsi.account_block
+          WHERE (account_block.author_account_id = (NULLIF(current_setting('jwt.claims.account_id'::text, true), ''::text))::uuid)
+        UNION ALL
+         SELECT account_block.author_account_id
+           FROM maevsi.account_block
+          WHERE (account_block.blocked_account_id = (NULLIF(current_setting('jwt.claims.account_id'::text, true), ''::text))::uuid))))))))));
 
 
 --
@@ -4491,6 +4533,7 @@ GRANT SELECT ON TABLE maevsi.account TO maevsi_anonymous;
 --
 
 GRANT SELECT,INSERT ON TABLE maevsi.account_block TO maevsi_account;
+GRANT SELECT ON TABLE maevsi.account_block TO maevsi_anonymous;
 
 
 --
diff --git a/src/deploy/function_events_invited.sql b/src/deploy/function_events_invited.sql
index b07fc5c..d84396e 100644
--- a/src/deploy/function_events_invited.sql
+++ b/src/deploy/function_events_invited.sql
@@ -10,7 +10,7 @@
 
 BEGIN;
 
-CREATE OR REPLACE FUNCTION maevsi_private.events_invited()
+CREATE FUNCTION maevsi_private.events_invited()
   RETURNS TABLE(event_id uuid)
 AS $$
 DECLARE
@@ -19,25 +19,29 @@ BEGIN
   jwt_account_id := NULLIF(current_setting('jwt.claims.account_id', true), '')::UUID;
 
   RETURN QUERY
-  SELECT event_id FROM maevsi.invitation
+  SELECT i.event_id FROM maevsi.invitation i
   WHERE
     (
-      contact_id IN (
+      i.contact_id IN (
         SELECT id
         FROM maevsi.contact
         WHERE
           account_id = jwt_account_id
-		  -- The contact selection does not return rows where account_id "IS" null due to the equality comparison.
-		  AND
-		  -- contact not created by a blocked account
-		  author_account_id NOT IN (
-			SELECT account_block_id
-			FROM maevsi.account_block
-		    WHERE b.author_account_id = jwt_account_id
-		  )
-		)
+          -- The contact selection does not return rows where account_id "IS" null due to the equality comparison.
+          AND
+          -- contact is not a blocked user and is not authored by a user who blocked jwt_account_id
+          author_account_id NOT IN (
+            SELECT blocked_account_id
+            FROM maevsi.account_block
+            WHERE author_account_id = jwt_account_id
+            UNION ALL
+            SELECT author_account_id
+            FROM maevsi.account_block
+            WHERE blocked_account_id = jwt_account_id
+          )
+      )
     )
-    OR id = ANY (maevsi.invitation_claim_array());
+    OR i.id = ANY (maevsi.invitation_claim_array());
 END
 $$ LANGUAGE plpgsql STABLE STRICT SECURITY DEFINER
 ;
diff --git a/src/deploy/function_invitation_claim_array.sql b/src/deploy/function_invitation_claim_array.sql
index 365833a..7d67781 100644
--- a/src/deploy/function_invitation_claim_array.sql
+++ b/src/deploy/function_invitation_claim_array.sql
@@ -9,31 +9,35 @@
 
 BEGIN;
 
-CREATE OR REPLACE FUNCTION maevsi.invitation_claim_array()
+CREATE FUNCTION maevsi.invitation_claim_array()
 RETURNS UUID[] AS $$
 DECLARE
-  _arr UUID[];
-  _result_arr UUID[] := ARRAY[]::UUID[];
-  _id UUID;
+  _invitation_ids UUID[];
+  _invitation_ids_unblocked UUID[] := ARRAY[]::UUID[];
+  _invitation_id UUID;
 BEGIN
-  _arr := string_to_array(replace(btrim(current_setting('jwt.claims.invitations', true), '[]'), '"', ''), ',')::UUID[];
-  FOREACH _id IN ARRAY arr
-  LOOP
-    -- omit invitations authored by a blocked account
-   IF NOT EXISTS(
-	  SELECT 1
-	  FROM maevsi.invitation i
-	    JOIN maevsi.contact c ON i.contact_id = c.contact_id
-	    JOIN maevsi.account_block b ON c.author_account_id = b.blocked_account_id
-	  WHERE i.id = _id and b.author_account_id = current_setting('jwt.claims.account_id', true)
-	) THEN
-      _result_arr := append_array(result_arr, _id);
-	END IF;
-  END LOOP;
-
-  RETURN _result_arr;
+  _invitation_ids := string_to_array(replace(btrim(current_setting('jwt.claims.invitations', true), '[]'), '"', ''), ',')::UUID[];
+  IF _invitation_ids IS NOT NULL THEN
+    FOREACH _invitation_id IN ARRAY _invitation_ids
+    LOOP
+      -- omit invitations authored by a blocked account
+      IF NOT EXISTS(
+	      SELECT 1
+	      FROM maevsi.invitation i
+	      JOIN maevsi.contact c ON i.contact_id = c.contact_id
+	      JOIN maevsi.account_block b ON c.author_account_id = b.blocked_account_id
+	     WHERE i.id = _invitation_id and b.author_account_id = current_setting('jwt.claims.account_id', true)
+	    ) THEN
+        _invitation_ids_unblocked := append_invitation_array(result_invitation_ids, _invitation_id);
+	    END IF;
+    END LOOP;
+  END IF;
+  RETURN _invitation_ids_unblocked;
 END
-$$ LANGUAGE PLPGSQL STRICT STABLE SECURITY INVOKER;
+$$ LANGUAGE PLPGSQL STRICT STABLE SECURITY INVOKER
+;
+
+COMMENT ON FUNCTION maevsi.invitation_claim_array() IS 'Returns the current invitation claims as UUID array.';
 
 GRANT EXECUTE ON FUNCTION maevsi.invitation_claim_array() TO maevsi_account, maevsi_anonymous;
 
diff --git a/src/deploy/function_invitation_contact_ids.sql b/src/deploy/function_invitation_contact_ids.sql
index e3f0f9b..aa84939 100644
--- a/src/deploy/function_invitation_contact_ids.sql
+++ b/src/deploy/function_invitation_contact_ids.sql
@@ -11,21 +11,29 @@
 
 BEGIN;
 
-CREATE OR REPLACE FUNCTION maevsi.invitation_contact_ids()
+CREATE FUNCTION maevsi.invitation_contact_ids()
 RETURNS TABLE (contact_id UUID) AS $$
 BEGIN
   RETURN QUERY
-    SELECT invitation.contact_id FROM maevsi.invitation
-    WHERE id = ANY (maevsi.invitation_claim_array())
+    SELECT i.contact_id FROM maevsi.invitation i
+    WHERE i.id = ANY (maevsi.invitation_claim_array())
     OR (
-	   event_id IN (SELECT maevsi.events_organized())
-	   AND
-	   -- omit contacts authored by a blocked account or referring to a blocked account
-	   contact_id NOT IN (
-		 SELECT c.id
-		 FROM maevsi.contact c
-		   JOIN maevsi.account_block b ON c.author_account_id = b.blocked_account_id OR c.account_id = b.blocked_account_id
-		 WHERE b.author_account_id = NULLIF(current_setting('jwt.claims.account_id', true), '')::UUID
+	    i.event_id IN (SELECT maevsi.events_organized())
+	    AND
+	    -- omit contacts authored by a blocked account or referring to a blocked account
+	    i.contact_id NOT IN (
+        SELECT c.id
+        FROM maevsi.contact c
+        WHERE c.account_id IS NULL
+        OR c.account_id NOT IN (
+          SELECT blocked_account_id
+          FROM maevsi.account_block
+          WHERE author_account_id = NULLIF(current_setting('jwt.claims.account_id', true), '')::UUID
+          UNION ALL
+          SELECT author_account_id
+          FROM maevsi.account_block
+          WHERE blocked_account_id = NULLIF(current_setting('jwt.claims.account_id', true), '')::UUID
+        )
 	   )
 	);
 END;
diff --git a/src/deploy/table_account_block.sql b/src/deploy/table_account_block.sql
index 8182dbe..2bba97f 100644
--- a/src/deploy/table_account_block.sql
+++ b/src/deploy/table_account_block.sql
@@ -17,6 +17,6 @@ COMMENT ON TABLE maevsi.account_block IS E'@omit update,delete\nBlocking of an a
 COMMENT ON COLUMN maevsi.account_block.id IS '@omit create\nThe blocking''s internal id.';
 COMMENT ON COLUMN maevsi.account_block.author_account_id IS 'The id of the user who created the blocking.';
 COMMENT ON COLUMN maevsi.account_block.blocked_account_id IS 'The id of the account to be blocked.';
-COMMENT ON COLUMN maevsi.account_block.created_at IS E'@omit update,delete\nThe timestamp when the blocking was created.';
+COMMENT ON COLUMN maevsi.account_block.created_at IS E'@omit create,update,delete\nThe timestamp when the blocking was created.';
 
 COMMIT;
diff --git a/src/deploy/table_account_block_policy.sql b/src/deploy/table_account_block_policy.sql
index c2d45c4..19f7212 100644
--- a/src/deploy/table_account_block_policy.sql
+++ b/src/deploy/table_account_block_policy.sql
@@ -6,6 +6,7 @@
 BEGIN;
 
 GRANT INSERT, SELECT ON TABLE maevsi.account_block TO maevsi_account;
+GRANT SELECT ON TABLE maevsi.account_block TO maevsi_anonymous;
 
 ALTER TABLE maevsi.account_block ENABLE ROW LEVEL SECURITY;
 
@@ -16,11 +17,11 @@ CREATE POLICY account_block_insert ON maevsi.account_block FOR INSERT WITH CHECK
   author_account_id = NULLIF(current_setting('jwt.claims.account_id', true), '')::UUID
 );
 
--- Only allow selects for blocked accounts authored by the current user.
+-- Only show rows where the current account is involved.
 CREATE POLICY account_block_select ON maevsi.account_block FOR SELECT USING (
-  NULLIF(current_setting('jwt.claims.account_id', true), '')::UUID IS NOT NULL
-  AND
   author_account_id = NULLIF(current_setting('jwt.claims.account_id', true), '')::UUID
+  OR
+  blocked_account_id = NULLIF(current_setting('jwt.claims.account_id', true), '')::UUID
 );
 
 COMMIT;
diff --git a/src/deploy/table_contact_policy.sql b/src/deploy/table_contact_policy.sql
index 8652d14..e5fba06 100644
--- a/src/deploy/table_contact_policy.sql
+++ b/src/deploy/table_contact_policy.sql
@@ -15,49 +15,61 @@ ALTER TABLE maevsi.contact ENABLE ROW LEVEL SECURITY;
 
 -- Only display contacts referencing the invoker's account, omit contacts authored by a blocked account.
 -- Only display contacts authored by the invoker's account, omit contacts referring to a blocked account.
--- Only display contacts for which an accessible invitation exists, omit contacts auhored by a blocked account or referring to a blocked account.
+-- Only display contacts for which an accessible invitation exists.
 CREATE POLICY contact_select ON maevsi.contact FOR SELECT USING (
   (
-	  account_id = NULLIF(current_setting('jwt.claims.account_id', true), '')::UUID
-	  AND
-	  author_account_id NOT IN (
-		  SELECT blocked_account_id
-		  FROM maevsi.account_block
-		  WHERE author_account_id = NULLIF(current_setting('jwt.claims.account_id', true), '')::UUID
-	  )
-	)
-	OR
-	(
-      author_account_id = NULLIF(current_setting('jwt.claims.account_id', true), '')::UUID
-	  AND
-	  account_id NOT IN (
-		  SELECT blocked_account_id
-		  FROM maevsi.account_block
-		  WHERE author_account_id = NULLIF(current_setting('jwt.claims.account_id', true), '')::UUID
-	  )
-	)
-    OR id IN (SELECT maevsi.invitation_contact_ids())
+    account_id = NULLIF(current_setting('jwt.claims.account_id', true), '')::UUID
+    AND
+    author_account_id NOT IN (
+      SELECT blocked_account_id
+      FROM maevsi.account_block
+      WHERE author_account_id = NULLIF(current_setting('jwt.claims.account_id', true), '')::UUID
+      UNION ALL
+      SELECT author_account_id
+      FROM maevsi.account_block
+      WHERE blocked_account_id = NULLIF(current_setting('jwt.claims.account_id', true), '')::UUID
+    )
+  )
+  OR
+  (
+    author_account_id = NULLIF(current_setting('jwt.claims.account_id', true), '')::UUID
+    AND
+    (
+      account_id IS NULL
+      OR
+      account_id NOT IN (
+        SELECT blocked_account_id
+        FROM maevsi.account_block
+        WHERE author_account_id = NULLIF(current_setting('jwt.claims.account_id', true), '')::UUID
+        UNION ALL
+        SELECT author_account_id
+        FROM maevsi.account_block
+        WHERE blocked_account_id = NULLIF(current_setting('jwt.claims.account_id', true), '')::UUID
+      )
+    )
+  )
+  OR id IN (SELECT maevsi.invitation_contact_ids())
 );
 
--- Only allow inserts for contacts authored by the invoker's account
--- No blocked account can be invited
+-- Only allow inserts for contacts authored by the invoker's account.
+-- Disallow inserts for contacts that refer to a blocked account.
 CREATE POLICY contact_insert ON maevsi.contact FOR INSERT WITH CHECK (
   author_account_id = NULLIF(current_setting('jwt.claims.account_id', true), '')::UUID
   AND account_id NOT IN (
-	SELECT blocked_account_id
-	FROM maevsi.account_block
-	WHERE author_account_id = NULLIF(current_setting('jwt.claims.account_id', true), '')::UUID
+    SELECT blocked_account_id
+    FROM maevsi.account_block
+    WHERE author_account_id = NULLIF(current_setting('jwt.claims.account_id', true), '')::UUID
   )
 );
 
 -- Only allow updates for contacts authored by the invoker's account.
--- No contact referring to a blocked account can be updated
+-- No contact referring to a blocked account can be updated.
 CREATE POLICY contact_update ON maevsi.contact FOR UPDATE USING (
   author_account_id = NULLIF(current_setting('jwt.claims.account_id', true), '')::UUID
   AND account_id NOT IN (
-	SELECT blocked_account_id
-	FROM maevsi.account_block
-	WHERE author_account_id = NULLIF(current_setting('jwt.claims.account_id', true), '')::UUID
+    SELECT blocked_account_id
+    FROM maevsi.account_block
+    WHERE author_account_id = NULLIF(current_setting('jwt.claims.account_id', true), '')::UUID
   )
 );
 
diff --git a/src/deploy/table_event_policy.sql b/src/deploy/table_event_policy.sql
index 63f1f0f..7a1493f 100644
--- a/src/deploy/table_event_policy.sql
+++ b/src/deploy/table_event_policy.sql
@@ -14,11 +14,11 @@ GRANT INSERT, UPDATE, DELETE ON TABLE maevsi.event TO maevsi_account;
 
 ALTER TABLE maevsi.event ENABLE ROW LEVEL SECURITY;
 
--- Only display events that are public and not full and not organized by a blocked account
+-- Only display events that are public and not full and not organized by a blocked account.
 -- Only display events that are organized by oneself.
+-- Only display events to which oneself is invited, but not by an invitation authored by a blocked account.
 -- Only display events to which oneself is invited, but not by an invitation authored by a blocked account
 CREATE POLICY event_select ON maevsi.event FOR SELECT USING (
--- Below copied to function `maevsi.event_invitee_count_maximum`.
   (
     visibility = 'public'
     AND
@@ -27,18 +27,22 @@ CREATE POLICY event_select ON maevsi.event FOR SELECT USING (
       OR
       invitee_count_maximum > (maevsi.invitee_count(id)) -- Using the function here is required as there would otherwise be infinite recursion.
     )
-		AND author_account_id NOT IN (
-			SELECT blocked_account_id
-			FROM maevsi.account_block
-			WHERE author_account_id = NULLIF(current_setting('jwt.claims.account_id', true), '')::UUID
-		)
+    AND author_account_id NOT IN (
+      SELECT blocked_account_id
+      FROM maevsi.account_block
+      WHERE author_account_id = NULLIF(current_setting('jwt.claims.account_id', true), '')::UUID
+      UNION ALL
+      SELECT author_account_id
+      FROM maevsi.account_block
+      WHERE blocked_account_id = NULLIF(current_setting('jwt.claims.account_id', true), '')::UUID
+    )
+  )
+  OR (
+    author_account_id = NULLIF(current_setting('jwt.claims.account_id', true), '')::UUID
   )
-	OR (
-		author_account_id = NULLIF(current_setting('jwt.claims.account_id', true), '')::UUID
-	)
   OR (
-		id IN (SELECT maevsi_private.events_invited())
-	)
+    id IN (SELECT maevsi_private.events_invited())
+  )
 );
 
 -- Only allow inserts for events authored by the current user.
diff --git a/src/deploy/table_invitation_policy.sql b/src/deploy/table_invitation_policy.sql
index 4f61ea6..d957f1d 100644
--- a/src/deploy/table_invitation_policy.sql
+++ b/src/deploy/table_invitation_policy.sql
@@ -28,33 +28,39 @@ CREATE POLICY invitation_select ON maevsi.invitation FOR SELECT USING (
       FROM maevsi.contact
       WHERE account_id = NULLIF(current_setting('jwt.claims.account_id', true), '')::UUID
 
-	    EXCEPT
+      EXCEPT
 
-	    -- contacts to oneself authored by a blocked account
-	    SELECT c.id
-	    FROM maevsi.contact c
-	      JOIN maevsi.account_block b ON c.account_id = b.author_account_id AND c.author_account_id = b.blocked_account_id
-	    WHERE c.account_id = NULLIF(current_setting('jwt.claims.account_id', true), '')::UUID
+      -- contacts to oneself authored by a blocked account
+      SELECT c.id
+      FROM maevsi.contact c
+        JOIN maevsi.account_block b ON c.account_id = b.author_account_id AND c.author_account_id = b.blocked_account_id
+      WHERE c.account_id = NULLIF(current_setting('jwt.claims.account_id', true), '')::UUID
     )
   )
   OR (
-	  event_id IN (SELECT maevsi.events_organized())
-	AND
-	  contact_id NOT IN (
-	    SELECT c.id
-	    FROM maevsi.contact c
-	      JOIN maevsi.account_block b
-	      -- contact authored by a blocked account OR referring to a blocked account
-	      ON c.author_account_id = b.blocked_account_id OR c.account_id = b.blocked_account_id
-	    WHERE b.author_account_id = NULLIF(current_setting('jwt.claims.account_id', true), '')::UUID
-	  )
+    event_id IN (SELECT maevsi.events_organized())
+  AND
+    contact_id IN (
+      SELECT c.id
+      FROM maevsi.contact c
+      WHERE c.account_id IS NULL
+      OR c.account_id NOT IN (
+        SELECT blocked_account_id
+        FROM maevsi.account_block
+        WHERE author_account_id = NULLIF(current_setting('jwt.claims.account_id', true), '')::UUID
+        UNION ALL
+        SELECT author_account_id
+        FROM maevsi.account_block
+        WHERE blocked_account_id = NULLIF(current_setting('jwt.claims.account_id', true), '')::UUID
+      )
+    )
   )
 );
 
 -- Only allow inserts for invitations to events organized by oneself.
 -- Only allow inserts for invitations to events for which the maximum invitee count is not yet reached.
--- Only allow inserts for invitations issued to a contact that was created by oneself
--- Do not allow inserts for invitations issued to a contact referring a blocked account
+-- Only allow inserts for invitations issued to a contact that was created by oneself.
+-- Do not allow inserts for invitations issued to a contact referring a blocked account.
 CREATE POLICY invitation_insert ON maevsi.invitation FOR INSERT WITH CHECK (
   event_id IN (SELECT maevsi.events_organized())
   AND (
@@ -68,18 +74,18 @@ CREATE POLICY invitation_insert ON maevsi.invitation FOR INSERT WITH CHECK (
       FROM maevsi.contact
       WHERE author_account_id = NULLIF(current_setting('jwt.claims.account_id', true), '')::UUID
 
-	    EXCEPT
+      EXCEPT
 
-	    SELECT c.id
-	    FROM maevsi.contact c
-	      JOIN maevsi.account_block b ON c.account_id = b.blocked_account_id and c.author_account_id = b.author_account_id
-	    WHERE c.author_account_id = NULLIF(current_setting('jwt.claims.account_id', true), '')::UUID
-	  )
+      SELECT c.id
+      FROM maevsi.contact c
+        JOIN maevsi.account_block b ON c.account_id = b.blocked_account_id and c.author_account_id = b.author_account_id
+      WHERE c.author_account_id = NULLIF(current_setting('jwt.claims.account_id', true), '')::UUID
+    )
 );
 
 -- Only allow updates to invitations issued to oneself through invitation claims.
--- Only allow updates to invitations issued to oneself through the account, but not invitations auhored by a blocked account
--- Only allow updates to invitations to events organized by oneself, but not invitations issued to a blocked account or issued by a blocked account
+-- Only allow updates to invitations issued to oneself through the account, but not invitations auhored by a blocked account.
+-- Only allow updates to invitations to events organized by oneself, but not invitations issued to a blocked account or issued by a blocked account.
 CREATE POLICY invitation_update ON maevsi.invitation FOR UPDATE USING (
   id = ANY (maevsi.invitation_claim_array())
   OR
@@ -89,24 +95,32 @@ CREATE POLICY invitation_update ON maevsi.invitation FOR UPDATE USING (
       FROM maevsi.contact
       WHERE account_id = NULLIF(current_setting('jwt.claims.account_id', true), '')::UUID
 
-	  EXCEPT
+    EXCEPT
 
-	  SELECT c.id
-	  FROM maevsi.contact c
-	    JOIN maevsi.account_block b ON c.account_id = b.author_account_id and c.author_account_id = b.blocked_account_id
-	  WHERE c.account_id = NULLIF(current_setting('jwt.claims.account_id', true), '')::UUID
+    SELECT c.id
+    FROM maevsi.contact c
+      JOIN maevsi.account_block b ON c.account_id = b.author_account_id and c.author_account_id = b.blocked_account_id
+    WHERE c.account_id = NULLIF(current_setting('jwt.claims.account_id', true), '')::UUID
     )
   )
   OR
   (
     event_id IN (SELECT maevsi.events_organized())
-	  AND
-	  -- omit contacts authored by a blocked account or referring to a blocked account
-    contact_id NOT IN (
-	    SELECT c.id
-	    FROM maevsi.contact c
-	      JOIN maevsi.account_block b ON c.author_account_id = b.blocked_account_id OR c.account_id = b.blocked_account_id
-	    WHERE b.author_account_id = NULLIF(current_setting('jwt.claims.account_id', true), '')::UUID
+    AND
+    -- omit contacts authored by a blocked account or referring to a blocked account
+    contact_id IN (
+      SELECT c.id
+      FROM maevsi.contact c
+      WHERE c.account_id IS NULL
+      OR c.account_id NOT IN (
+        SELECT blocked_account_id
+        FROM maevsi.account_block
+        WHERE author_account_id = NULLIF(current_setting('jwt.claims.account_id', true), '')::UUID
+        UNION ALL
+        SELECT author_account_id
+        FROM maevsi.account_block
+        WHERE blocked_account_id = NULLIF(current_setting('jwt.claims.account_id', true), '')::UUID
+      )
     )
   )
 );
@@ -116,7 +130,7 @@ CREATE POLICY invitation_delete ON maevsi.invitation FOR DELETE USING (
   event_id IN (SELECT maevsi.events_organized())
 );
 
-CREATE OR REPLACE FUNCTION maevsi.trigger_invitation_update() RETURNS TRIGGER AS $$
+CREATE FUNCTION maevsi.trigger_invitation_update() RETURNS TRIGGER AS $$
 DECLARE
   whitelisted_cols TEXT[] := ARRAY['feedback', 'feedback_paper'];
 BEGIN
diff --git a/src/revert/function_invitation_claim_array.sql b/src/revert/function_invitation_claim_array.sql
index 2e1283c..35671f4 100644
--- a/src/revert/function_invitation_claim_array.sql
+++ b/src/revert/function_invitation_claim_array.sql
@@ -2,6 +2,6 @@
 
 BEGIN;
 
-DROP FUNCTION maevsi.invitation_claim_array;
+DROP FUNCTION maevsi.invitation_claim_array();
 
 COMMIT;
diff --git a/src/sqitch.plan b/src/sqitch.plan
index 7f3d006..f4e039a 100644
--- a/src/sqitch.plan
+++ b/src/sqitch.plan
@@ -21,12 +21,12 @@ table_event_group [schema_public role_account role_anonymous table_account_publi
 index_event_group_author_username [table_event_group] 1970-01-01T00:00:00Z Jonas Thelemann <e-mail+maevsi/sqitch@jonas-thelemann.de> # Add an index to the event group table's author_username field.
 table_event [schema_public role_account role_anonymous table_account_public] 1970-01-01T00:00:00Z Jonas Thelemann <e-mail+maevsi/sqitch@jonas-thelemann.de> # Add table event.
 function_events_organized [privilege_execute_revoke schema_public table_event role_account role_anonymous] 1970-01-01T00:00:00Z Jonas Thelemann <e-mail+maevsi/sqitch@jonas-thelemann.de> # Add a function that returns all event ids for which the invoker is the author.
-function_invitation_claim_array [privilege_execute_revoke schema_public role_account role_anonymous] 1970-01-01T00:00:00Z Jonas Thelemann <e-mail+maevsi/sqitch@jonas-thelemann.de> # Add a function that returns the current invitation claims as UUID array.
 index_event_author_username [table_event] 1970-01-01T00:00:00Z Jonas Thelemann <e-mail+maevsi/sqitch@jonas-thelemann.de> # Add an index to the event table's username field.
 enum_invitation_feedback_paper 1970-01-01T00:00:00Z Jonas Thelemann <e-mail+maevsi/sqitch@jonas-thelemann.de> # Possible choices on how to receive a paper invitation: paper, digital.
 table_contact [schema_public role_account role_anonymous table_account_public] 1970-01-01T00:00:00Z Jonas Thelemann <e-mail+maevsi/sqitch@jonas-thelemann.de> # Add table contact.
 table_invitation [schema_public table_event table_contact] 1970-01-01T00:00:00Z Jonas Thelemann <e-mail+maevsi/sqitch@jonas-thelemann.de> # Add table invitation.
 function_events_invited [privilege_execute_revoke schema_private schema_public table_invitation table_contact role_account role_anonymous] 1970-01-01T00:00:00Z Jonas Thelemann <e-mail+maevsi/sqitch@jonas-thelemann.de> # Add a function that returns all event ids for which the invoker is invited.
+function_invitation_claim_array [privilege_execute_revoke schema_public table_invitation table_contact table_account_block role_account role_anonymous] 1970-01-01T00:00:00Z Jonas Thelemann <e-mail+maevsi/sqitch@jonas-thelemann.de> # Add a function that returns the current invitation claims as UUID array.
 function_invitation_contact_ids [privilege_execute_revoke schema_public table_invitation function_invitation_claim_array function_events_organized role_account role_anonymous] 1970-01-01T00:00:00Z Jonas Thelemann <e-mail+maevsi/sqitch@jonas-thelemann.de> # Add a function that returns all event ids for which the invoker is invited.
 table_contact_policy [schema_public table_contact role_account role_anonymous function_invitation_contact_ids] 1970-01-01T00:00:00Z Jonas Thelemann <e-mail+maevsi/sqitch@jonas-thelemann.de> # Add policy for table contact.
 function_invitee_count [privilege_execute_revoke schema_public table_invitation role_account role_anonymous] 1970-01-01T00:00:00Z Jonas Thelemann <e-mail+maevsi/sqitch@jonas-thelemann.de> # Add a function that returns the invitee count for an event.
diff --git a/src/verify/table_account_block_policy.sql b/src/verify/table_account_block_policy.sql
index 6d0d9e1..b21bded 100644
--- a/src/verify/table_account_block_policy.sql
+++ b/src/verify/table_account_block_policy.sql
@@ -8,7 +8,7 @@ BEGIN
   ASSERT (SELECT pg_catalog.has_table_privilege('maevsi_account', 'maevsi.account_block', 'SELECT'));
   ASSERT NOT (SELECT pg_catalog.has_table_privilege('maevsi_account', 'maevsi.account_block', 'UPDATE'));
   ASSERT NOT (SELECT pg_catalog.has_table_privilege('maevsi_account', 'maevsi.account_block', 'DELETE'));
-  ASSERT NOT (SELECT pg_catalog.has_table_privilege('maevsi_anonymous', 'maevsi.account_block', 'SELECT'));
+  ASSERT (SELECT pg_catalog.has_table_privilege('maevsi_anonymous', 'maevsi.account_block', 'SELECT'));
   ASSERT NOT (SELECT pg_catalog.has_table_privilege('maevsi_anonymous', 'maevsi.account_block', 'INSERT'));
   ASSERT NOT (SELECT pg_catalog.has_table_privilege('maevsi_anonymous', 'maevsi.account_block', 'UPDATE'));
   ASSERT NOT (SELECT pg_catalog.has_table_privilege('maevsi_anonymous', 'maevsi.account_block', 'DELETE'));