The Kindle has an innovative cover attaching mechanism that works really well. However, it may be that it is causing some problems. The cover attaches with two hooks that slip into two small slots on the side of the Kindle. If you try to attach the cover the wrong way, or pull back on the back cover you could easily crack the Kindle case, however.
I just received an email from Amazon Customer Service giving me instructions on how to use the cover and warnings about how improper use can crack or damage the Kindle. This type of mailing would only be done if Amazon is experiencing problems with this happening. I wonder if the cover mechanism will be changed in the future.
This has been an issue for quite a while. There is/was some kind of lawsuit or threat of lawsuit if I recall correctly (read about on either MobileRead or KindleBoards).
My Kindle 2 was bought on release day along with a cover and although I’ve had no problems I did remove the cover after receiving the email and see that the top hook is bent upwards. The email makes it sound like it should be straight. As far as I remember it’s always been bent, but it’s only been off the Kindle twice during the year.
There absolutely was a settlement, one of the most reasonable ones I’ve ever heard of (lawyers walked away with $50,000 in fees). I talked about it a couple of weeks ago, if you’re interested:
http://www.thelewisfour.com/2010/01/kindle-2-screen-cracking-lawsuit.html