Academia - Do we need a post notice for possibly controversial questions?

I would expect that such labels should be applied rarely, if at all. But it wouldn't necessarily be a bad thing to have the option available to us.

Yes, please add this. And no, I don't think we should add this sparingly. I would propose to aggressively add this to questions that have a potential to be controversial. If used too much it does not matter (the warning does not say anything that's not true for all questions anyway), and if it salvages just a few questions that would otherwise get derailed it's a win.

(OTOH it will only help if the diamond mods actually do end up aggressively removing argumentative answers and comments without notice, as the warning would indicate - in my opinion this has not really been the case in the past)