A2QFI - not sure Ebay will bother - if someone wants to sell items that are within Ebay's rules then they won't be fussed. I've just watched a used phone go for £10 more than O2 sell new (pre-pay, not contract), and I heard a lady being interviewed who made a lot of money buying items from M&S and auctioning them on Ebay.com as M&S would not ship stateside.
There's plenty of fools out there just waiting to be parted from their money. So long as the seller of the key-rings ships the product he's in the clear.