I can think of two incidents that really apply:
1. At an interview. I have my volunteer stuff listed on my resume, and it turns out the manager had a son on one of the local area teams. Gave us a chance to talk FIRST for a bit, and I did end up getting the job
2. Airport TSA officer. I was going through security with that darned LRI vest, and got pulled aside... turns out I had, at some point that weekend, stuck a potentiometer in one of the pockets. And of course, having a "switch" as the first lady called it, along with all the other stuff I keep in there, was suspicious. after about 15 minutes (I had the distinct impression someone in a backroom somewhere was running a background check on me), she introduced me to one of her "friends" to talk to - he must have been 7 feet tall and was built like a tank. So I started explaining everything all over again, and he interrupted me with "Oh, you're with FIRST? we can get this taken care of". I got to go on my way pretty quickly after that!