I thought this was interesting, I don’t have a Canon – (I went for the Nikon and love it!).
I guess a lot of companies now just make one camera (or any item of technology) and then put a “dumbed down” firmware onto each version to allow it to open up certain features. We do something kind of similar at work, the code is all the same and your “keyfile” opens up certain functionality – it means theres only one codebase to maintain (although interactions can make testing and code complexity a big issue!).
Do you have any items where you’ve reprogrammed (in some way) the system to give you extra features? DVD Players, Car Engine management systems?! Whatever?