What's the right behavior for sensor removal?

[nbcl-maronoff]

If the user wants to delete a sensor from the sensors list, but that sensor is in use by another workflow, what happens? (Incidentally, I'm almost sure this is where our sensor-deletion crash is coming from.)

• It can't allow the user to remove the instances of the sensor from other workflows that have data, because that alters the information about that workflow.
• It can't prevent the user from ever deleting a sensor; what if the user set up a sensor that hasn't been used in a year, but was used in a capture before it was retired?

My first instinct is to include a new field called something like "deleted" in the data model. If a sensor is marked as "deleted", it no longer appears in the sensor list, and when you open a workflow using a deleted sensor, it's either grayed out or has some other representation that indicates you can't use it for capture anymore.

Question 1: If a workflow uses a deleted sensor, should the operator be able to create a new person and capture data for that person using all sensors except the deleted one?

Let's see if I can tag @nbcl-rossm here. Looks like I can. Also, @nbcl-kkgreene should look at this.