A rating system is a helpful method to lessen the chance a child is exposed to violent games, however they still can get access to it at their friends house. In any case harboring a child away from video games is not an answer, if anything they will one day be exposed to such violence and crave it more. Parents should try to parent instead of letting their TV do the job for them, and then getting mad when it doesn't. For the game creator and producers it is a way to cover their backs. With a rating it show the audience that the game is focused toward, so should an incident like columbine arise and the focus turns to the gaming industry, the companies have a way out.
Ratings are ideal for the parents of the young gamer as well.
They do however understand rating systems. When their child goes to a movie that is rate 'R' the parent automatically know what the type of content is involved with that movie. This will be the same process with the video games. I wholeheartedly approve of ratings for games. However, there is a loophole that is just now coming to the movie industry.