It's mainly annoying when you're trying to pull multiple packs, since you need to change your route if you don't have any voice communication with your healer.

There was one really confusing instance I had with it, where this WHM in A1N would keep up Med 2 on everyone... on Faust... which basically meant I had to go Defiance just to keep the adds from killing them...

But aside from that, it's pretty much just 4mans where this happens and it's usually resolved by just telling them not to do that. If it doesn't, vote kick 'em or leave.