I addressed all this in an earlier post in this thread. Ebay "Authentication" for watches does
not make any attempt to check for stolen items. the authenticator (Stoll & Co) compare the item received from the seller, to what was advertised in the Ebay auction, to determine if the watch is the same one that was listed, (e.g. not a Chinese clone if the ad said it was an authentic Swiss watch). NCIC doesn't apply here at all. I have asked Ebay to consider adding this as an additional step in their authentication process, but I think it entirely unlikely that will happen. In most states in the USA, pawn shops are required by law to check items they receive against the NCIC database, and if stolen, take possession of said items and turn them over to law enforcement. Seems reasonable to me, Ebay should be forced to do the same, otherwise it just becomes a channel for stolen goods.
I would like to add, Ebay hides behind several legal protections when it comes to the buying and selling of stolen goods on their platform. First, Ebay is shielded by Section 230 of the Communications Decency Act, which gives them immunity since they are neither buyer or seller and as long as they didn't know it was a stolen item. Second, they only have to remove a live auction if they are properly notified it is a stolen item, and there are hoops you have to jump through for that. Third, after a auction is complete and the item is sold, they don't even want you to contact them at all, they tell you go report it to law enforcement, its a criminal issue, once subpoenaed they will hand over information. As for Ebay providing reimbursements, that is not policy. They have a "Moneyback Guarantee" policy but that mostly covers when the seller doesn't ship your item, or what you got is grossly different than was was advertised. It specifically does not cover stolen goods, although if the anecdotal reports of some people getting Ebay reimbursement for stolen items is true, it would have been done using this policy as its the closest policy that applies.