I bought my Tron Pro from a Pinsider based on pictures only. Prior to that, I bought two pins from a regular on rec.games.pinball. As rai stated, it can be a little nerve racking and nothing is 100%. I also looked at the history of the fellow on Pinside, read some of his posts etc. PMed back and forth a bit, a little info on his work and eventually a voice call. If I am going to wire a guy more than 2k, I want to at least speak with them. I also had to get his home address for booking the truck pick up. Lastly, his bank details for wire processing.

Thankfully in all cases, my games arrived exactly as expected (Lotr, Ngg, Tron - shipping from US to Canada). I have been fortunate to deal with some really good guys but if my spidey senses tingled even for a second, I would have likely backed out. However, I guess the best scammers are the guys who lull you into a sense of security.