Those that haven't spent them already, are now having them removed.
A glitch in the Xbox LIVE Rewards programme managed to dish out 1000s of
free MS Points to a number of players last night.
Those that noticed the extra points had been added to their accounts
jumped on the Marketplace to start spending their free currency before
it was removed. More honest gamers, however, decided to let Microsoft
know.
In a reply from Xbox Support on Twitter, the response was: "We
appreciate your honesty. Enjoy your points."
Another reply said a similar thing: "There was a known issue with the
rewards system. The points you were rewarded are yours."
That said, gamers who refrained from spending their free points soon
found the extra credit was removed. Microsoft has since changed its
stance on the situation, it seems.
"There was an issue with Rewards points being deposited multiple times,"
reads a Tweet explaining the situation, "the extra points are being
recalled."
http://www.videogamer.com/news/xbox_live_rewards_glitch_gives_1000s_of_free_ms_points.html