Currently there are no rules but AI posting shouldn't be allowed for people to just copy and paste responses with no effort. In certain circumstances it could be ok as long as it's quoted and noted that it's AI generated content in a similar way that another's work you are relaying should be quoted and sourced. If it's not then it's the same as plagiarism to me.
The problem with these accounts is a real dilemma because it is more than just getting merit points in order to upgrade the membership in the shortest possible time. Those accounts that adopt this method will get opportunities they do not deserve, and they will either rush to join one of the signature campaigns to take a place that would have been deserved by someone more worthy than them, especially if the campaign pays for posts in local boards, and therefore they will not stop using AI (I noticed many accounts posting In the gambling section in a completely suspicious way, but it is not easy to prove manipulation), or they gain a reputation due to their upgraded accounts that enable them to manipulate, spread false information, or deceive other users who are unaware of anything, especially new visitors to the forum. Not to mention those who will be able to take a loan from the loan board, that will compensate them for all the effort they have made in a short time.