I've all but given up on eBay and Craigslist.

Guy tried to pass a bent frame.

Another guy tried to sell Speedplay X-Series pedals with Zero cleats. When I called him on it he threw the pedals into his Mercedes and screeched off in anger.

Dura Ace shifters "work flawlessly" and then don't when actually in-hand. Seller goes completely dark.

And on and on...