Well, of course there’s nothing that can be used to prevent training an AI, just like there’s nothing preventing monkeys from stealing cameras and taking pictures. It’s what happens next that matters.
The Internet Archive didn’t get sued over copyright, even though it had electronic copies of lots and lots of copyrighted works (and even let people “check out” copies), until they changed their distribution model to allow unlimited lending. Nothing about how they gathered their works changed, it was the change in distribution that got them sued.