I read a post on a gamespot forum suggesting that people that get this glitch are still vulnerable to melee combat:
[quote from user Bunions on gamespot forum]
However when playing in Village yesterday I found something very helpful. Their was an invincible guy in the corner of one of the side houses. Everyone was shooting him, throwing grenades. (He should stood there shooting people - hehe). Until after quite a while of this, I went up next to the guy and did a full blown gesture melee attack. The first time it knocked off his helmet; but the second time it killed him! I found this pretty cool, but since then I couldn't find anyone else who was invincible to try it out. So next time you see one of those jerks, try that.
And another response in that thread:
[quote from primeboss]
oK I just tried it Twice.
The first time it didn't Kill him, probably because it didn't do enough damage before he killed me.
The second time on a different person It DID kill him, but killed me like 5 times before i could enough damage to kill him.
PS: The map was Village.
Hopefully this will help deal with people exploiting this glitch somewhat.