I'm starting to suspect some posts are AI-written,
Same here. I have also started to suspect the same. I have been monitoring one account for the last few weeks, and within this time, the account have posted 3/4 times only which seems like AI generated to me. I don't want to publicly post that until I'm sure that he is posting AI generated text.
This will be somewhat a disaster if someone with a long list of account starts to participate in signature campaign and post AI generated garbage, I'm pretty much sure we will see the day in the coming future.
The problem is that how will you proof that a message is AI written or self written ?
One way to go about is that you will find all of his posts in a similar pattern of AI generated text but what if he uses AI in some of his posts and he writes other posts himself. Then i guess it will be even more difficult to judge when there will be mixtures of AI and self written text.