Ebay seller Smcomstore (SportsMemorabilia.com) sells items they do not possess.
http://www.ebay.com/itm/Mickey-Mantl...item4d2576b425
I outed them a few years ago when they were listing and selling Derek Jeter forgeries certed by Global Authentics.
I once spoke to a rep from SM and he told me "We have a autograph contract with Derek Jeter."
Of course, it was a total lie.
They scour Ebay listings, copy the auction, mark up the price and then they list the item.
I do find it unethical if they (SportsMemorabilia.com) don't get permission from the owner and original Ebay seller of the item.