I had a run in with one such jerk at RISAA.
While talking to a plug builder/seller who has already chimed in on this thread, a guy over hears me ask the seller if he has a particular plug in his locked display case. Seller is over heard by the jerk as he says, "yes-I'll hold it in the back for you." 30 seconds later the jerk asks for the plug being held for me. In shock, and knowing I can get another one from the builder at a later date, I say in disgust- "TAKE IT!" That was Friday of RISAA. Monday that plug is for sale, at a mark up, on SOL. Turns out the guy is also flipping stuff from local shops on SOL and even on ebay.
And I thought we were all in this sport to help each other enjoy our resource...
Woody