The glitch uses an RPG called the Javelin, which fires a rocket up into the air, which then arcs back toward the ground. So you can fire over obstacles and such.
Bring out your javelin, press and hold the "throw grenade" button, press the swap weapons button, release the grenade button. Now when you die, your javelin RPG instantly explodes at your location, killing anyone within 20 feet or so. Equip the Danger Close perk and you get more range on the explosion. The enemy just took the bunker on Wasteland? Swap to this setup and run in there, you'll kill everyone inside because THEY shot YOU. They could just not shoot you, then you can run around knifing them all and they can't stop you.
Yes, this is something "built into the game", but it's more than just a playstyle or equipment loadout. (like the running around all fast knifing people, or dual wielding the extremely powerful model 1887 shotguns). You know what else is "built into" the game? On the Afghan map, there's a rock you can glitch yourself into so you're invincible but can still shoot anyone that runs by. That should get you banned too.