HiPhish: ...When you type your PIN into an ATM machine the machine doesn't have to connect to any server base to confirm your PIN, that would be a gigantic security hole, instead your PIN is checked locally using a mathematical algorithm; no one except you ever knows the right PIN. In the same way there is no reason why you'd have to connect to a server to validate your key.
There is quite a big difference, though, which means that wouldn't work in this case. If you were to install a bank machine, and disconnect it from the bank's servers, then maybe it would be able to accept pins from people who already have accounts. Of course, whether it would let you withdraw money without being able to tell the main server to adjust accordingly is another matter, but that's neither here nor there. The thing is, if you then went to the bank and set up an account (equivalent to buying a key for T2), and then went back to the bank machine, without giving it access to the banks' server in the meantime, would you expect it to accept your pin?? Of course not, as it's not had access to find it out.
Now, it could be said that when you download it, it could include a 'list' of all the bought codes, which could be updated whenever someone buys a new code. Not only would that be opening the system to piracy (defeating the original point of the activation, which can be argued as right/wrong/futile if you wish), but it'd mean you'd need an internet connection anyway!
I'm not sure if activations are necessary or not. I haven't played T2, and have very little interest in doing so. I just felt I needed to point out how unreasonable the demands you made actually are.
Oh, and that 'massive security hole' you mentioned, sending personal information about your account across the internet? Has it occurred to you that it could (and quite potentially is, I don't know) just be encrypted to send it? There are a number of methods available that would take a supercomputer several centuries to decode if it had to guess the correct prime number (which is never sent over the internet). I assume you trust those methods as secure, as you've presumably used them to buy games on GOG.