Can't be trusted. I was the high-bidder for a headphone auction on Audiogon for which the seller cancelled at the very last second. This seemed suspicious to me, so I sent a contact to Audiogon asking for an explanation. In response, they emailed the seller asking for an explanation. The seller gave some spiel about being called out of town suddenly as to why they cancelled the auction. Audiogon's response to the seller: "Perhaps you can message the buyer when you are able to re-list the item."
Wow. This was my first experience with Audiogon. This is also my last experience with them. I guess I got off light, since I didn't lose anything but time. But my time is valuable, and not to be wasted. I doubt this would have happened on ebay.