Auctions are not the best idea at big shows since it takes away sales from the floor as people drag their feet and wait for the auction to buy stuff. If the show has a swap meet, then project games will be in the auction rather than the swap. The buyers fees/tax just add cost to already expensive games and goes to a middle man. If you are in favor of the auction please explain why adding 15-20% onto the purchase is a good thing. If I go to a show, I am expecting to pay cash, no fees and definitely not paying sales tax.
If people want to bring games for sale then put them on the floor with a for sale tag. I think the TPF organizers need to get rid of the auction and if FUN! or whoever wants to have an auction then do it separate. I don't think the auction is a big draw for TPF.