QUOTE(Hollandius @ Oct 30 2009, 07:29 PM)

Maybe Halo 3 ODST got a new check. The Xbox calculates a checksum of unique files on the disc and sends them to microsoft. If two Xboxes sent the same checksum ... Microsoft knows thats a copy. Just like a Key for a online game, you cant play online with the same key (like on the very early counter-strikes versions (before steam))
That wouldn't make sense as all originals are carbon copies of each other.