Except for a few specific categories of items that go through authentication, eBay never sees what the seller ships or the what the buyer receives, so there is nothing for eBay to check unless someone complains about what was received by invoking eBay's money back guarantee.
Sellers are responsible for the descriptions they provide, and buyers should not assume that eBay screens the listings in advance.
As long as counterfeits exist and there are folks trying to sell them, buyers will still have to be on the lookout for them, and avoid deals that are obviously too-good-to-be-true, whether they are being sold by accounts registered overseas or by domestic sellers wittingly or unwittingly buying counterfeits from overseas to sell here.
Buyers that doubt their ability to distinguish a genuine article from a counterfeit one should only consider purchasing from trustworthy sellers that have an established reputation for delivering exactly what was described, and should avoid deals that are too-good-to-be-true, or deals that are offered by inexperienced sellers that might disappear soon after the transaction is made.
