We're using a Volunteer tag as a pseudo-role in Populi for our records and, hopefully in the near future, for campus communications. The problem is that while you can inactivate a person's role in order to remove them from mailing lists including that role, you can only remove a tag from a person entirely. We have a rather large number of volunteers, so manually including active ones or excluding inactive ones isn't feasible.
I have a couple of less than optimal workarounds in mind, but the ability to inactivate tags to exclude them from communications would be a good solution for us. I feel like this would be far easier to implement than custom roles for Populi's dev team as well.