You're right. But I wish the rule would be applied the same way for crawling. Perhaps anytime someone is down by choice they are fair game! Cause I think most would agree that it really sucks when someone pulls guard by flopping on their back and laying there. But, that's just more stuff that's discretionary and will leave things sooo debateable. Guess we'll just go back to Pride rules are UFC 1 rules!
the thing is though if your knee is on the ground it can actually cause significantly more damage than if it is just a hand.