Well one for the idea to hide stuff is never the idea. But there should be a fee to start for putting something up on the AH. Add a timer to how long an item will stay up for sale. If they choose to cancel their AH item for sale then charge a hefty fee to cancel it. If they want 1k for an item charge 25% fee of what they were asking. If they don't want to cancel it they can simply waiting the 3 or 5 days for the auction to end.