No need for his merit to be removed. If truly the person used AI and people agree to it, why not just leave him neutral trust and state the reason and put the reference link. It is better this way.
Well I wouldn't agree anyway with your suggestion even though it makes sense because they have been an existing pattern of stereotyping shit posters of AI content generators which Charles-Tim mentioned above and probably even though such user emerges as a higher ranked member he's still going to be know for such actions because the trust system keeps it open to audience to see his tags, which is enough punishment for me and reducing the merit or deleting the already earn merit from them is not what I think.
I know about that, but as I have observed; neutral feedback or trust mostly doesn't stop them from participating in bounty campaigns and they would still rank up, join them, and keep doing what they are doing unless they get banned, and in most cases, users aren't banned for doing something that gets them a neutral trust. Bounty campaigns usually only has a rule against red trust and say nothing about neutral trust.
With the user, he will very possibly be banned and I have no issue with merit of a banned user. Sometimes, merit history will be helpful for checking too, so deduction of merits in your suggestion is not good. It's like cleaning all history for the banned user.
They don't get banned all the time, and it won't clean all the history of merits for banned users but only the ones that they received on posts that broke forum rules. Besides, we have tools and platforms that archive data from the past for reference in the future.
I also would like to ask! how exactly d o you want this your suggestion to be implemented? is it by a long and gigantic coding? because basically the forum is built of SMF so making changes like this requires a lots of coding and time since it has been a for a long time.
Obviously, it can only be done by coding.
I'm not an expert when it comes to coding or web development, but I think it shouldn't be that big of a problem, a condition added on deleted posts by moderators for deleting the merits received in that post should do the work, but whether how easy or complex this can be, only @PowerGlove can tell us.