I have reason to believe that i have found a cheater on Xbox live. It seems he is using a program that removes the game off his GT, still keep the gamer score but the game doesn't show up on his tag. I found this out on a Xbox 360 gaming website which shows "stats". Basically on this site it says he has a certain amount of gamer score on a game but when you check his tag the game doesn't show. I have checked the Gamer tag on different consoles and gamer tags but it still says the same. If possible i would like to speak to a member of the Xbox Live enforcement team to provide more details.