FUD Zilla reports about the javeline exploit in Call of Duty: Modern Warfare 2. The site reports that rather than fixing the bug, Microsoft is punishing users who abuse this glitch:
Stephen Toulouse, the director for policy and enforcement for the Xbox 360's Xbox Live online service said that players who abuse the "javelin missile exploit" will be banned from the entire Xbox Live service. In some cases it may even make a permanent if the exploit is badly abused.
The javeline exploit is a glitch in the online multiplayer. You switch to the javeline missile launcher after "cooking" a semtex grenade by holding down the grenade throw button. This locks the player's actions. When the player dies the javeline missile explodes, killing all enemies within an enormous radius.