I was using Ghost Pro (hides name and removes red crosshairs when enemies look at you) Warlord Pro and Hacker Pro. Look for small patches of grass and lay there while doing the grenade glitch. Or if there isn't anything, lay in the open, the enemy will generally think you're a dead body. One guy ran into me and spun around to shoot but he never looked down. Its a really fun thing to do in HQ.
If any of you are considering doing this, I suggest doing it in non-hardcore game types. In regular gametypes, people are less aware of their surroundings, I tried in HC and was killed almost every single time. Either this is true or people are becoming wise to this trick, I hope not.