I have spent along time closely working around Car Auctions.
And from what i have seen over the years....YES everbody gets robbed at auctions, Sellers and Buyers.
Its the Auction houses that make the money, Not the seller and on average the buyers pay too much, by the time all the Fees & Vat are added.
There are ofcoarse expeption to this and on a good day, some bargins to be had, Just read the small print first. (although local car auctions to me, Currently DO NOT advertise the full fees, You have to ASK for them prior to Bidding / Selling. Bit noughty Really. )