on steam you can (or could, not sure if still works) hijack someones account temporary (enough time to steal tf2 items, but they increased a lot the security of this hole, and now if you reset an account you need to wait days til you can trade)
you could buy a physical game for cheap, give the code to someone (or sell it) them request steam support the account get stolen... then you had to take a picture of the phisical game with the receipt and a code writed with a pen..
then you were granted the account all you had to do was to steal the inventory and sell it to a banker or something like that..
sometimes when a person is not aware of the account stealed, they might think the account no longer works and think its gone... leaving the account for the thief forever...