I have a hard time believing that AI can be used to label AI-generated videos without there being a significant number of false positives/negatives. I think back to ZeroGPT and it labeling the Declaration of Independence as AI-generated.
Cryptographically verifiable provenance and chain of custody is going to be necessary to get to the human only stuff, before long, but the good AI stuff will be better. Just a matter of time, at this point.