I noticed yesterday that a seller I purchased from several times states in her current auctions that if an item is returned, there will be a 15% restocking fee. It seems like a good idea from a seller's point of view, because the 15% will help cover fees associated with the relisting of the item, but is it enforceable? (I assume this applies only the item is returned within a set amount of time with all of the original security tags intact.) Is there an official eBay policy about this? Thanks!