Super Smash Bros Violence? Inappropriate Conduct?

My 7 year old son is insistent that I buy him the video game, "Super Smash Bros." for the Wii. I am concerned that the game may be quite violent. I have read about the game and it is rated T for teenagers, and because of violence. He says that all the kids at his school already have it, are other parents really so irresponsible? I've read the game is a "fighting game," does this indicate blood? I've also heard there are many crude jokes relating to farting. How do I teach my son that farting is inappropriate in public? Will realizing that farting is inappropriate convince him that this game is inappropriate and that is why I can't buy it for him?