Mastro consignors not paid yet?

[Rob D.]

To take Brian's point further: What happens if, after I pay for a card that I bought in a Mastro auction, I destroy it (or, more realistically, it accidentally gets destroyed)?

If the answer is that I have to make restitution of the selling price to the original consignor -- in effect paying for the card twice, once to Mastro and again to the consignor -- then you might want to try to come up with something better.