A permanent ban is never issued hastily, even when it comes to cases where plagiarism is more than evident.
I can not remember it for a permanent ban but as far as I can remember there were some cases where members were temp ban for small mistakes like joining a giveaway thread which was not a giveaway thread but it looked like a giveaway thread and things like that.
What, in my opinion, is the biggest problem is actually the lack of rules regarding the use of AI on the forum, and if you don't have rules, then some members obviously think that they can write their posts with the help of AI.
First of all we need a clear clause to add in the unofficial rules, then we can think about the rest.