Recently, people have started doing "Mystery Auctions" in which they don't state what the are selling. I think that this is unfair to everyone, and is technically a form of scamming. My suggestion is to have a rule stating that you must tell everyone what you are auctioning.
Have you ever seen the show "Storage Wars"? The whole point of the "Mystery Auctions" (Minewars) is to mimic that show. The idea is that you don't know if it's good or not, and to gamble. There's is nothing against the rules for this, and you are aware of this when you are taking place in it. If you don't think it's fair, don't participate.
I don't think this will happen. It's not really scamming if you think about it. By putting up a "Mystery Auction" people who bid have to realize that they might not get what they thought they would. People have to realize the consequences of bidding, and that they could lose a lot of money.
Same concept still,just not on a large scale. If you want to take the gamble, go ahead. If you don't, then don't bid.