I think the moderators haven't decided how to deal with post generated by ChatGPT, but it's just because the content generated by ChatGPT has been exposed if some part was took from the other article. As been mentioned by @mprep here, so my assumptions if someone have created a post generated by ChatGPT and it's really looks like created by human, it's fine since no one able to investigate it.
Well, since @hilariousandco already banned at least two accounts due use of chatbot, I think that they pretty much decided what to do in those cases. Tricky part is to prove that someone actually used chatbot, but if you manage to do that I don't think that mods/admins will hesitate too much.
Yes, please do, though obviously they will need a little more verification so might not get handled straight away. It's probably going to get out of hand fast with these issues now. Personally I think it might be wise to look into disabling sigs on all new users/lower ranks until people have earned the right to have one through acquiring a large amount of merit.