I mean yeah I agree, enforcing something like this is going to be very very difficult. But there are several clear examples of something like DallE generating images very similar to or nearly identical to copyrighted IP.

IANAL, but I presume a claimant could be able to establish some reasonable certainty to a court that licensed works were used in a way that breaks the license, at which point OpenAI (or really any AI company) would be responsible for defending their practice or non-use of those licensed works