I'm not surprised that they take it out on marketplace sellers. Unless it's fulfilled by Amazon (in which case the seller shipped it directly to Amazon, and the only shipment to the end buyer is from Amazon's warehouse to the buyer) marketplace orders are shipped directly from buyer to seller. Some sellers will print out the Amazon invoice and throw it in the box, but the shipping label won't reflect it at all 99% of the time.

This is one reason why I'm hesitant to buy expensive products (technology, luggage, etc.) from international sources. I didn't really expect that Trusted Traveler revocation might be on the line for something that a third party shipped directly to you, but I had figured that if I bought knockoff headphones from an overseas deal site, that the shipment itself might be subject to seizure.

How can Amazon, eBay, etc. reliably tell who is a legitimate vendor and who isn't, barring some verification process that would be cumbersome, expensive, and drive a lot of sellers away? It's easy to issue refunds reactively and ban the seller from the site, it's a lot harder to proactively verify that they are shipping real stock (especially since a third party could enroll by shipping the genuine article, pass inspection, and then switch out to fakes once they've been approved).