reminds me of a little scam we used to do I heard about when I was in the Navy. Ship pulls into port in the Philippines, sailors would bypass “authorized” currency exchange (official exchange rate was, say, 4 Philippine pesos per dollar), sailors would go to marketplace, buy pesos at 6 per dollar, have good time, go back to ship, stop at “official” currency exchange on the way back, buy dollars at 4 pesos; sometimes came back with more dollars than when left!