I think that part of the idea (very simplified from my meager weak brain) is that the Cuban economy is not supposed to benefit from any kind of U S commerce. If any of us went there, we would have to spend some money, ergo, we can't go. also can't buy, import or have in our possession any Cuban goods. We once stopped at a tobacco shop in Sault Ste Marie just before reentering the US after a hunting/fishing trip near White River. DH thought he would like to have a few cigars. Canadian customs doesn't care, we can carry as many as we'd like over the border. American customs on the other hand isn't so happy about it. We really had to think about how much it was worth to get a box of cigars. The penalties for smuggling contraband can be higher than you want to pay.