How would you even employ a checks and balances system o.o An RPer thinking someone is doing something right or wrong is purely subjective? Unless you're the GM considering you made the rp and thus know it and its rules etc intrinsically enough to know if a player is doing something wrong on an rp level. Personality/attitude wise, as has already been mentioned... if a GM is an asshat, then a player should just leave and join another rp or make their own. 

I'm curious to know what rps you're thinking which are living and thriving with notably abusive GMs, because having kept an eye on the forums and noting which rps are long lasting and thriving and the type of GMing and communication that goes in them... there aren't any abusive GMs. And if there was, I'd like to give the players the benefit of the doubt to know that this is the case and they wouldn't be subjecting themselves to anything like that and already know to just leave and find another rp. Unless they were masochistic or something, lol.