It's actually a bit more complex than just making up serial's it would cost a hell of a lot more money to manufacture carts that are all unique, this even applies to PC games, the only difference is that PC. Games are bundled with a unique code, the CD has no idea what this code is, that just the game and is the same on every disk made they just have a algorithm that will be able to tell if the code that you type in is at least correct for the game, once you connect to the internet it verifies that the code is legit and hasn't been used before then it ties it to your account or computer












