Actually, its probably easier that you think. For instance, when someone on here says "I'll get this pick". They then buy the pick, and post it minutes later. I'm sure if the capper is searching the rx boards, he can just see how many people bought the pick in between both posts.
The cappers could also cross-reference the list with the location (since most people show what location they are from).
oh, see what you mean but it should not be a hindrance....can pm it to a bud to post