You *can* backup a music CD. But not a DVD.
Wanna know why? Because making a personal backup is legal.
Reverse Engineering is highly illegal.
And to copy something with protection, such as a DVD, you need to use tools that are based upon reverse engineering of the security code.
Same goes for games.
However I think it's a load of BS to try and stop me copying my own games. I'm so not taking an original copy of a $100 game to a LAN. Sorry, aint happening.
So yeah. I copy what I paid for, reverse engineered or not :D
Edit: yes. I am an idiot who likes to Reserve Engineer :P