The way I see it, if you open the door for the government to legally enforce ratings (or even worse, run the ratings board) then you open the door for them to censor or outright ban whatever they deem inappropriate. You only need to look at the situation with games in Australia to see how bad things could get anywhere else where the government gets involved with handing out or enforcing ratings. I personally have absolutely no desire to have a government body of any kind tell me what I can and can't play.