Good point. That fake commit addendum means that the entire commit contents would not be under copyright protection. AI generated code is not currently copyrightable.
If AI generates code, and one just renames some variables/method signatures, then what?
Subpoena the provider they use.
Even if they don’t retain the full context, they have to save API calls for billing and analytics. If you’re clauding for the hour up to and after the commit, one can reasonably assume you built it with (if not exclusively by) AI.
That's not beyond a reasonable doubt.