I think I see what you are thinking of here but just stop and think about this one: Why can't you drive a car across the border to Canada or Mexico and sell it there? "Hey, Dude! Wanna buy a nice car?" Well, probably because, assuming you could sell the thing without being ripped off, beaten up or even killed stone dead then you will have to make it back across the border with a whole load of cash while the new owner will have to explain just where he came up with his new car. I don't suppose it could be any simpler with an airplane, could it?
You think you could get out of Mexico okay with $10 thousand in cash? Are you feeling that lucky? Now imagine leaving Africa with $100 thousand. Or will you take a check? If so, no need to go all the way to southern Africa, I know plenty of guys in West Africa ready to do a deal with you!