Nah they wouldn't all have involved studs. In fact I think there's a case to be made that Robertson McCoy was already free by the time he stamped. I think your point is really a wrong one. Getting stamped on by lads over 100kg wearing metal studs is not really proper retribution for a hold. Holding someone is sly and outside the rules, stamping is pure scumbaggery. It's up there with cheap shots and gouging as something pretty much guaranteed to start a fight.