It would be able to "ban" people from posting in your threads. Say, someone is a scammer or they spam or you just dont really like them, they wouldnt be able to post in threads made by you. Of course trusted/mediator would be counted out of the people that can be banned.

this could cause some problems, for example the accused not being able to reply in a scammer accusation topic

also it was suggested and turned down before, I believe