I finally found the info. It's called the Global Shipping Program.http://pages.ebay.com/help/buy/shipping-globally.html
Basically, it allows US sellers with international buyers to ship to a central US location. A company prepares the item, ships it outside the US, and receives the customs fees that are tacked on to your order. I can see why a seller would want to use the program -- as long as the parcel has tracking and is received by the global shipping provider, the seller has met eBay's requirements for shipping. If the item gets lost after leaving the US, the seller is not responsible.
If you still want to buy from US dealers on eBay, you should ask them if they use the program. The seller for your DC 52 boxes states at the end of the descritption that he/she ships this way, but I don't see how a buyer would know what that means.