I love the artwork, Poster formerly known as Nurgle5. Is that the concept sketch for the new Huron model?
Anyway... The actions of your Jackhole opponent would earn a good pimp-slap from me! I love beating braggarts like that that act like every move you make plays into their hands. I had this guy who giggled when I told him I played guard, after we had agreed to a game, and said "huh, good luck!". I promptly beat him on turn 1, in close combat! THE most satisfying win I have EVER had, lol. It was a low points game in an escalation league we were having at the shop, and he ran a Demon Bomb with one lieutenant Infiltrating. He charged, killed a few guardsmen. My turn, I pile in with the 7 troopers left and my tech Priest, they kill him, game over, turn 1! LOL
I would ask the staff to keep an eye out for any "extra" wargear cards the guy ends up with, then confront him in front of the group to let everyone see who they're dealing with.