This is still a problem for OSS licensing, since in order to license a work you need to be the copyright holder.

This might mean that OSS projects find it even more difficult to assert their licenses against violators in court, since they would need to prove that the part of the code that was copied was not AI output.

Banning the output of AI tools in OSS codebases is a sensible move for any project that actually cares about enforcing the license that their code is released under.