AI watermarks feel like they're approaching the problem from the wrong side - no matter what it will be possible to remove the watermark (Via manual rewriting, local LLLMs, etc). Instead it seems like we need "proof of human creation". And the only way I see that being possible is hardware-attested proof of keypresses. Which obviously has huge privacy implications, but how else would you actually know that a piece of content was produced by a human pressing keys on a keyboard? The proof would also need to include timestamps for the keypresses, so tell if someone is just copying from another window.