This afternoon both Major Nelson and Stepto posted on Twitter that the enforcement teams on the Xbox live network were out in full force catching up on score corrections for cheaters and achievement hackers.
Major Nelson writes
“As I post this, we’ve begun taking steps to reset the Gamerscores of the offending players. As I have mentioned in the past, this is something we do occasionally to keep the service free of cheating in order to maintain a fair and level playing field for everyone. If you play fair and earn your achievements without glitching or cheating, you have nothing to worry about.”
While Stepto cautions:
“the best way to avoid a Gamerscore reset is…earn your achievements!”
If your Gamerscore did get reset your probably going to want to read the Gamerscore correction FAQ
Can’t say I blame them… Get out there and play clean.