You will be banned from playing on Modern Warfare 2, not on any other game, or even steam community. Even if you get banned, you can always still play with MW2 Liberation. This tool was made 2/3 years ago and it's still working, proves that Activision doesn't care about their old games, they can't even spend some time fixing this.
And yes, I'm banned and I can still play, even with cheats, since VAC bans are delayed and I'm banned already so =P