I think walkie talkies would work. You leave one in the stands, give one to each of your drive team + human player, and have one in the Pit. The idea is that each part of the competition containing your members have a non-failing method of communications. Coordination and wearing something destinctive helps to find people too. For instance, Metal Mustangs are known for our silver cowboy hats. Look through a crowd, and we're pretty darned easy to spot. Worst comes to worst, take the buddy system to the extreme. I hear handcuffs are cheap around this time
