They're just tilting at windmills. It's already difficult enough to catch cheaters in chess, where there are, at most, a few dozen candidate moves in any position. This is a space with infinite candidate moves.
Best case scenario is that they catch a few people who have no idea how to create art otherwise. But, short of an exam-like proctoring system where art can only be created under complete supervision, I doubt there's anyone in the whole world who can reliably distinguish a creation that is 90% AI / 10% human from 100% human.
I agree it will be hard or impossible to catch cheaters. But you get it backwards: AI generated art probably is more easily detectable. A chess game can be represented in a relatively small number of bytes, while artwork must represented with a much larger number. That means more opportunities to find an unintentional signal of provenance (e.g. artefacts that aren't readily noticeable to humans).
Best case scenario is that they catch a few people who have no idea how to create art otherwise. But, short of an exam-like proctoring system where art can only be created under complete supervision, I doubt there's anyone in the whole world who can reliably distinguish a creation that is 90% AI / 10% human from 100% human.