We tend to assume patches will fix problems. Looks like that's... not really the case with Modern Warfare 2.
A recent patch that made its way to both Xbox 360 and PS3 versions of the game appears to have created more issues than it fixed. The hefty upgrade has, at least on Xbox LIVE, unintentionally "unlocked" various mods that have drawn in problems similar to those suffered by PC online gamers: hacks.
Of all things that made it through, God Mode is probably the worst being reported. Other mods include higher jumps, infinite ammo, wall hacks, and infinite AC130 usage.
If you haven't run into any of these, there's a video below, made by someone doesn't seem to mind the hacks at all. Not surprisingly, the poster has disabled comments for his video.