@MartinSleziak I waited a bit whether I get some response here - since I got no feedback I used my best judgement and created the account-suspension meta.mathoverflow.net/posts/3884/revisions. I suppose other users who visit meta might notice the new tag - and if they disagree they will react in some way (either by removing it or by voicing the opposition to the new tag on meta or in chat).

Probably this older question would deserve the tag too: When a MSE user is suspended, should the suspension apply to MO as well?

A quick search suspension is:q returns a few questions that mention suspension. (And by omitting is:q you can find a few more.)

I'd guess that a question concerning a specific account probably does not have to be bumped just to add the new tag: Protest for my account suspension.

The questions An Introduction to Suspension Theory is locked - so here question whether it should have this tag is completely irrelevant.

In this question answers mentions suspension, but it seems that the question is actually about account deletion: What is wrong with my account?