There's got to be rules somewhere.
I've heard of catastrophic injuries just in training from innocuous "slams" not higher than knees so I can see there's a safety issue there.
I've always been of the opinion though that if you f'ed up and let yourself git picked up because you didn't control posture or didn't hook a leg on a triangle, you let go or suffer the consequences. I guess they're taking the consequences out because they don't want a risk of those injuries because in a professional environment, some just decide to hold on.