I usually try to steal a reviewers badge. Then when you go into a room they play what ever CD you may bring. They also reward you with their "top self" liquor. They keep it in the bathroom under the sink and it usually not visible to the average show goer. A warning however, be sure to compliment them on the sound. Say something like, "the midrange sounds fuller this year and the bass is tighter, did you change the crossover or eliminate that annoying cabinet resonance?" That puts them off their game and gives you a chance to ask for a refill on your 30 year old scotch.