It depends. Just as there are Ai art generators there are also Ai art detectors which compare the images to a data base. They are not perfect. They work in a similar way to how there are programs that detect plagerism or nudity. You can get around said detectors by tricking said Ai but it does help a huge amount to filter.
Everything after that depends on users reporting your cover/comic. The final judgement comes from a Tapas Staff member. Identifying Ai art has many tells. While many beleive hands are the most obvious, it is not. You should actually check for other signs before the hands.
If you get wrongly accused of using Ai then Bella_Artz already said what they had to do to clear said suspicions.
Here.
I mean you have to prove it is not with solid evidence. Meanwhile your comic (and in some cases your account) would be suspended until the investigation is finished. I don't think it is worth arguing with tapas staff over a rule just for the sake of arguing. Especially if your comic will be suspended while the investigation is going on.