You must have been careless to get a ban ... only know one person who got a ban, and he was very obvious in what he was doing.
Mind you he also got away with swapping his console @ j-mart.
Buy a new box, swap drives, take console back for refund, make sure you mis-spell your name on the return docket.
They never take note of the console id's - guess they "could" follow it back to the original owner, but guess thats down to microsoft as they obviously cant be bothered.