[yeukhon]

Exactly. Even if your product was bought on US soil, sold on eBay to someone outside of the U.S., and then sold to the 4th party via the black market or 2nd hand market again, now it's legal that a NK spy picks it up. That's the same effect as saying "I picked up this US Dell computer from a recycle shipment from US to China last week." Yeah a lot of electronics are "re-used" that way oversea.

The U.S. government is aware of this but for as long as their US companies are never directly selling to NK the sanction is enforced from the US's perspective. This including banks cannot do transaction (via multiple middlemen? yes sure! Money laundering, but the FBI will be looking at it).