An R18+ rating would make game buying so much more easier. At the moment, I rarely buy anything that's not got an MA15+ rating, and even then, someone them don't warrant that rating :/
I play violent video games knowing that they are not real, that it's virtual. I don't want my gaming experience to be controlled just because some people can't differentiate between reality and a game. While, I'm normally a fan of a government having a say in our lives (especially health care), this is not one of those cases.