You should be able to be banned from a specific thread. Say, if you are making non constructive posts or being annoying, but nothing ban worthy, then your posts in that thread are hidden and you are unable to post in it anymore. Being banned from 3 threads results in a ban.
Waddayathink
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Isn't that what a post-collapse due to member reports does? It hides the offending post and lets the member know that their fellow member don't appreciate their particular kind of participation. It also has the promise of "a moderator is going to review this and decide if you dun goofed".