Prevent players from entering WG via icecrown during Wintergrasp event

So today, a multiboxer "played" in Wintergrasp. That would be okay and maybe even funny to play against him in usual manners but he made it so that it was impossible.

During all Wintergrasp event, while my team was defending, he kept jumping from Icecrown with all his toons using parachute and starfalling the entire group of people that just respawned out of the graveyard. Once he killed between 20-30 players like that, he went back to icecrown (maybe by keeping the pop up asking if he wants to enter Wintergrasp event and then pressing escape or hitting no to be teleported out of it) aaaand rince and repeat.

Correct me if i'm wrong but even if it's unfair (which people will just reply that i'm whining) it's mostly and obviously exploiting.

So it would be interesting to make it so that doing this kind of thing is not possible anymore, maybe by increasing the range that you're automatically queued for WG when you're in Icecrown, near Wintergrasp Keep or by forcing the player to effectively be considered as part of the event when he kills any player in Wintergrasp during said event.

Unfortunately I didn't take any video of this, however if anyone can post an evidence of what I am saying I would be really glad.

The head GM says they already ban for this so you can feel free to report them whenever you do catch some evidence.