> but I think it unlikely given the harm it would do to them to violate an enterprise contract in this way

That's if you have any reason to believe in the justice system to actually enforce that, which has already been proven complicated (although not impossible!) to demonstrate for copyrighted content.

At this point believing the frontier labs at their word is utterly naive. They have cheated and they will cheat if it gives them any hope of leaping ahead of their competitors.