An auction with an audience is the first place I would use to blow out a POS Vintage(old) car. I used to have a Volvo P1800( 1968 I think) and bought it not knowing it was filled with bondo. Not willing to sell it privately and face the buyer I went the auction route.
Things started falling apart when the auctioneer asked me to say something about the car in front of about 100 people. I cannot remember what I said because somebody bought that rustbucket anyway...
I never did look into the eyes of the buyer. I took my cheque and ran to the bank.....

Oh yes, buyer beware.