i just gave some... Shooting threw walls every kill is a headshot. Weapon mods you cant get. And taking 3 shots in the head and not dropping dead.
How do you exsplain people running about with weapons mods that are only for the devs?? And shooting threw walls?? And every kill is a headshot? There must mods or something.
One word.... Hardcore...
Joking, I'd imagine lag has a lot to do with that, with the exception of the dev weapons.
I'm pretty sure weapon unlocks are server side?