I've seen them bitten by dogs, driven over by multiple cars, heavily scratched by other family users who don't put them back into their cases immediatedly upon removal, scratched by those non-tray loading players and that's just my personal experience.
I'm sure others have seen tons of other ways where the CD is somewhat less sturdy than, say, Stonehenge.
My exact quote was: "DVD's and CD's are among the most durable products you can purchase" and I will stand by that. These things will be filling landfills for centuries. Plastic is durable. I still have my 45's purchased back in the early 60's and they still play, although not as well as CD's will years from now. Of course, they can get scratched or warped or broken.
I can't think of any other products that offer free replacements if your dogs chew them up or your children break them. Not sure why the music industry has to do that.