Thanks for the reports regarding "Super Speed" games in MW2 that popped up over the weekend.
We've updated the playlist to include a fix to prevent this from happening. The updated playlist may take up to an hour to prop to everyone.
You don't need to download an update, this is not a patch, it will simply update the next time you connect to multiplayer. If you're currently playing multiplayer, then when you restart, or back out to main menu and reload multiplayer, it will download the new gameplay settings.