I remember readig about this issue in Xbox mag. The game disc must be
used in the game system so that you can't go and copy it to use on other
systems. It's Microsoft's way of keeping piracy down. I'd personally
do the same thing if I worked very hard to create games myself. You may
be able to read about this at
www.xboxmagazine.com. Hope this breif
answer sheds light on your question.
G Man