Good luck getting a court to hear it when you won’t have a shred of evidence to show

Kinda? Not really, though. If anything it, the model’s response would just include “anti-commercial license” at the end and they’d get rid of that with further training

What is stopping corpos from scraping everyone’s posts and stuff from the fediverse and train their AI?

That very real and enforceable “this comment cannot be used to train AI” crap some people add to every comment that definitely makes bots not scrape the comment, of course!