I've been turned down for setting up lights for similar shows. Typically, its been because they didn't want 'studio' lighting, packs, heads, umbrellas, etc. Thats what many think of if you ask them about lighting.
So if I get a no, I ask specifically about camera mounted flashes and if the audience will be allowed to use P&S's with flash. If those are allowed, I am usually allowed to use an on-camera flash. I then place one or two in strategic locations and fire them remotely with a pocket wizard. Its usually just enough to make the difference by dropping the ISO about 2 stops and giving me better hand holding speed.
But if they aren't going to allow P&S's with flash, they probably won't allow a speedlight either. In that case, yea, higher ISO and faster lenses are about your only option. Its always worth a try.