Interesting thread, although I would never do this today, I did have a run in with these exact people when I was about 18. I was working at circuit city at the time selling home audio, so I had a small clue of what looking at.
Me and 3 friends were driving down the road when 2 guys in a white van started yelling at us that they had stolen speaker equipment and they wanted to sell it. Growing up in New Jersey, this was music to our ears.
Anyway, they opened the back of the van and had tons of speaker equipment saying it was stolen, very expensive to purchase retail, and very cheap for us. (about $200 bucks for 5 speakers and a sub). I ask them to open the box so I could make sure I was purchasing speakers, they declined and tried to talk us out of it.
We had a quick huddle and decided they were trying to rip us off. My friends (who were much much larger then the two 150lb salesmen) stood in front of the driver and passenger door, not letting them in. I told them that I am opening 1 box, if they were speakers then they had a sale, if they werent then they were going to get a couple punches in the face. They were very nervous. I opened one of the "main speakers" which had a 5 foot box and rather heavy. There was a wooden box with a car speaker installed in it!!! it wasn't even a quality speaker, it looked like it was out of a sub $15k american car from 1994. Paper cone and paper "horn" tweeter. Anyway my large friends had a field day with them.
Just thought you guys would like to hear that they got what they deserved.