While it's not nice to cheat, it's an entirely different thing to abuse a glitch, and a whole different pile of shit to be banned for doing so.
Glitches are IN THE GAME, FIX THEM!
If I was banned for using a glitch in the game, I'd definitely be having my lawyer give Bungie a call. I paid for the game (That so called glitch is in), I pay for Live and I am entirely in my rights to play it on Live. If you don't want people using glitches.....FIX EM YOU LAZY BASTARDS!
With that said, I don't even own a 360, let alone Halo 3. I jut hate lazy developers that would rather ban people than fix their own mistakes. I'd sue.