Will switching games from a game rental (e.g Blockbuster) really work? Odds of getting caught?

I got a Modern Warfare 2 for xbox360, and it messed up from console movement. Is it worth switching it with a game from Blockbuster or wasting money trying to fix itWill switching games from a game rental (e.g Blockbuster) really work? Odds of getting caught?
If you bought something and it messed something up then whoever's it was needs to fix it i.e. microsoft or infinity ward.