I've never done it for concerts but for sporting events, I've done it plenty. Ya can't sit all together unless someone pulls group ticket deal, which is a pain in the ass to do unless someone is willing to front the cash. I think 20 people will qualify for groups though I'm sure a check on the tickethellmaster site will tell you.
Anyways, for sporting events, we just hookup afterwards and talk about the experience. Since it's Vegas, there are PLENTY of restaurants with plenty of Alcohol available to those old enough to get a drink.
Oh and for those that don't know what a GTG is? It's a Get Together.
