There's a different sentiment on the original thread (see post #1). In any case, I think Mr. Witherwax will give sober consideration to any future nighttime paintball truck excursions.
Hindsight is 20/20. The more professional paintgun's look like shotguns at a glance. Especially if one is pointed at you in a non-paintball set up. The idiot was the one driving around with this thing, pointing it and shooting it at people for "fun". If it was a professional style paintball gun, these are NOT like the crap-ola ones you'll find at ToysR'Us. They're usually a 50 caliber size, and can approach muzzle velocities of a .45 caliber round. Get shot with one of those when you're not expecting it, with no protection, and the initial feeling is that you've been shot.
A paintball gun can cause disfiguring or blinding injuries if shot at a person's unprotected head. Anyone who is shot at by a stranger may reasonably fear that that person will fire a head shot (since the stranger has already shown a complete disregard for paintball safety). As such, it would seem that an unprovoked paintball attack should qualify as a threat of severe bodily harm meriting the use of deadly force in self-defense.