In systems engineering this was proven in court when you have one engineer writing specs and another implementing the "samish" system from those specs, but I'm not sure that would relate to any of the art assets made by the original authors of a game. I'd imagine any art, narrative writing or sound would still be considered IP, and without those things you don't have much of a game.

I suspect it won't stop people, and that it won't be much of an issue in a lot of cases. I wouldn't want to be the one to test it in any sort of court though. Not even on the other side of things, where it'll become even more of a nightmare to protect your indie IP on any form of platform which doesn't heavily regulate things.