Bungie Resets 15,000 Halo Reach Accounts
Bungie will be “applying credit resets” to approximately 15,000 Halo Reach players who used the Challenge Reset exploit. In additon to resetting the credits, they will employ a 1-day credit ban for warning purposes.
The exploit allowed users to complete a challenge a number of times by disrupting their internet connection. Its pretty clear that if you were doing this, you knew it wasn’t part of the game.