There are a handful of collectors and probably a few dealers who can tell a fake slab from a genuine slab. At least they can with the ones that have been identified and the diagnostics listed. But when it comes right down to it only the TPG can really tell for sure. So I think we're kind of stuck with that. As for a database of who owns what ? Never happen in a million years. Nor would it solve anything if it did. But if you want to protect yourself from buying fake slabs, that's easy. Buy only from respected and trusted dealers. That way even if they get fooled by one and you buy it from them, they'll stand behind it, for life. Other than that, you either become a pro at identifying fake slabs yourself - or you take your chances - because there is no way you, me or anybody else is ever to stop the counterfeiters.
I think too another way to protect oneself is be able to grade coins, not so much on the level of the graders at PCGS and NGC, but at least on a level to know if a slabbed coin is in fact a MS66 FBL or not. If the coin certainly does not possess all of the criteria it should for a MS66 and is in fact meeting a less than uncirculated condition, that may raise some flags to some people that something might not be kosher.
I have never bought a coin on Ebay. Much better customer quality control with Teletrade, Heritage and Great Collections. They get physical possession of the consigner coins, so if anything is fishy, the authorities get a call, the people there have them on speed-dial. I have been checking out PCGS' shared orders page, it has all invoices that people are willing to have other customers look at in terms of results. Amazing how many Chinese coins are getting submitted. There are the good Chinese who want to see this plague addressed through legal process.
I buy from eBay, but only from trusted dealers whom I know personally, and have done business with at local shows.
Yes, the problem is not ebay. The problem is some of the people who sell on ebay. Of course those same people often also sell at coin shows and/or out of a brick and mortar coin shop. There are good sellers on ebay. But you have to know who they are.
Well, I would call it "fraud". And there are all types of that, basically what you have are cheats gaming the system. Who gets hurt? Lots of folks, especially the companies they are scamming by duplicating their holders. They aren't going to try to counterfeit the lesser value company holders like Accugrade or NNC, what would be the point? Just wait until they start duplicating the old holder PCGS and NGC slabs, that would really throw me for a loop if they were able to pull that off especially the old rattlers.