As well as credit card fraud, I believe some shady key resellers buy keys in poorer countries where the game's price is low, and make a profit reselling the key

As well as credit card fraud, I believe some shady key resellers buy keys in poorer countries where the game's price is low, and make a profit reselling the keys in richer countries, for a price somewhere between what they paid for the key, and the legitimate price in that country. If the game is on sale in the poorer country, all the better for the reseller. With the Internet, I imagine this is all very easily done.