Hi ez0469,
An inherent problem with your solution is the following...
Now you buy the game, install it on your PC, it gets "activated", meaning that particular copy can be played on and only on your PC. (I'm not sure if you were saying if the installation or the "automatic backup CD" has your hardware identification burnt into it... but it doesn't matter anyway.)
A few months later you upgrade your PC. What do you do now? You gotta contact the game publisher again, to have your installation and/or backup CD (re)activated for your new hardware config. Well, just a bit of a pain in the @ss.
But what if you want to play the game again, say, five years later? You may have replaced all components in your PC by then. Perhaps, there's a very different operating system (new Windows; Linux; whatever) installed so you have to try the game in a virtual machine emulator (with the older Windows installed and some specific hardware config emulated). The game will not run and, even if the game publisher still exists, they won't help you anymore...
So, now you're left with a completely unusable original CD, backup CD and installed game. Even if your game is a retail version, not limited in the time of usage, number of installations etc. The next step? Finding a no-CD patch.
Joe