Keith, none of the discussion considered this;
Auction winner donates funds to the Non-profit, and receives a certificate saying they won the auction.
Winner then redeems the certificate to the organization that gives the item to them.
The item won in the auction is never owned or in the hands of the Non-profit.
The organization giving away the item receives nothing material from the winning bidder or non-profit. (since they didn't give the non-profit anything)
No quid-pro-quo because the winning bidder is dealing with two independent entities, one being the Non-profit, the other being the donating entity.
mmmm okey dokey ...
If you think that will fly, then I wouldn't want to be in your shoes when the IRS audits.
The "certificate" still has an inherent value that is equal to the product being auctioned. In fact, in IRS publication 526, it specifically addresses third party donations and the fact that the auction price is not deductible because the winner of the auction did not pay more than the fair market value of the item being auctioned. The damning bit is that the receipt of the item is dependent upon the person paying for the right to obtain it.
You and others can choose to be wrong if you like, but you don't have to believe me or the IRS, you can simply deduct your "donation" and then pray the IRS doesn't audit you and disallow your deduction.
Using your analogy, you could pay a pimp for the right to have sex with a hooker and that makes it ok (wife and girlfriend objections notwithstanding) ... I can hear it now ...
"But officer I didn't pay her for sex, I paid this other guy for a certificate that is redeemable for sex."
You and the hooker are still going to jail.