Authenticity is going to the make or break for this problem. However, I just haven't seen any promising solutions. Theoretically, there won't be solutions as the very intent of AI is to be human like in every way if achievable.
I recently tried a AI art detector while writing my latest - https://www.mindprison.cc/p/ai-art-challenges-meaning-in-a-w... - and found it to be abysmal. The false positives made it completely unusable.
I think platform holders saying "AI content is unwelcome here", and loudly kicking off violators is more than enough to send the required signal.
The goal is not to have 0% generated content, it's to brand yourself as _the_ source for thoughtful, human writing. Having an occasional article slip under the radar is fine.
There may be an appeal process, but the point is AI will make verification of authenticity painful.
My argument isn't "imperfect detection is fine".
I'm saying that _you don't need detection at all_.
Just make it very clear that AI content is unwelcome on your platform and loudly boot everyone who tries to "experiment" with your limits.