I have done it once and never again. I was selling a suburban and wanted $5,000. They went past the contract date of 6 months before they even responded to my questions about the car. When I demanded the car back after the date they said they had a seller and then gave me a bad check. I sued, won the case, went to collect and found out the company had done this before, has about 30 claims against them and wait in line. Eventually the guy went to jail, and they are closed. I am out $5,000. I try to make myself feel better by rationalizing the dealer was only offering me $2,000 at trade in and another used car lot was willing to buy it for $3,000. Blue Book for the truck at the time was over $8,000 in a private sale.
Lesson learned and It cost me $3,000 (I guess best offer) and a lot of agrivation. Going forward either trade it in or sell it privately. Auctions are also iffy, I did that once, but it depends what you own.
Most consigners have claims against them so it's tough to say this could be prevented. Most are OK, as long as they are in business and are planning to stay in bussiness, you never know. These guys had collector cars in the show room and decent references.
Best of luck,
Tytus