Highly selective enforcement along partisan lines to suppress dissent. Government officials forcing you to prove that your post is not AI generated if they don't like it. Those same officials claiming that it is AI generated regardless of the facts on the ground to have it removed and you arrested.

If you assume the use of law will be that capricious in general, then any law at all would be considered too dangerous for fear of use as a partisan tool.

Why accuse your enemies of using AI-generated content in posts? Just call them domestic terrorists for violently misleading the public via the content of their posts and send the FBI or DHS after them. A new law or lack thereof changes nothing.