Well, WakeUp, I can't speak for others. What I do though, is spot that dude sitting in the back, looking a little self-conscious and unsure, and say, "Hey man, I'm Keith, how you doing?" And we go from there. Gotta kind of feel it out a little bit, but if they are willing, sponsorship starts right then and there.
If they are unsure, no harm done. We talk a little, maybe I call them the next day to see how they are doing. Whatever feels right.