Once the data is legally delivered to your house, in most countries you can do whatever you want with it (and I'm not talking for the USA). That includes applying a patch to remove the protection (illegal only in a few countries, and even in those countries it would have to be fought in court before there's any certainty), or just typing a key you saw anywhere. Since publishing a suite of numbers/letters is totally legal, this mode of distribution would simplify the life of any "pirates" - just maintain a legal site with the keys available, and anybody can play the game without buying it and still do this 100% legally. They wouldn't even be "pirates" (man, I hate that word), that is they wouldn't be copyright infringers at all. Even if the key is only part of the protection, there's nothing a patch wouldn't solve, and since patches don't need to have any code from the original game, they'd also be perfectly legal for distribution in many countries. Plus, fighting legal battles about an user removing some protections with a patch would be far harder and more costly than suing file sharers, not to say quite impossible to catch.