I brought this up because I just broke a tab on my clear hard case and looked at the tab and realized it is literally a couple of hairs thick. Definitely a weakness. Back to Ebay for another one.
So as most know this is the biggest problem it seems with the hard cases for the D1 and D2 are the front faceplates staying in place. Designing a front faceplate with clips strong enough to keep it in place is tough because the gap tolerances between the upper and lower parts of the phone are so narrow. The clips have to be so paper thin in order to hook under the top face of the phone that they are weak and break very easy. The cheap Ebay hard cases and to a point even the higher quality cases like the Body Glove suffer from these weak points.
Motorola should have designed the screen face with hard cases in mind. All they had to do was design notches in the 4 corner edges of the screen face to allow hard case face plates something substantial to grab onto. The hard case designers could then mold slightly larger more durable clip designs into their top plates to grab those notches. It really is a design flaw if you ask me that Motorola didn't account for this knowing many users will be putting hard cases on them.