If an AI is able to consistently create content that doesn't break any of the forum's rules (good quality, on-topic, not just a padded word salad, no plagiarism, etc, etc)~
"AI" is plagiarism by definition. The only difference is it takes many more inputs and uses bits and pieces of all of them. The only good thing is that if enough people spam using AI, it can't train itself anymore because it's input will be generated by AI already.