I think this dash crack thing has more to do with the dash getting weaker and weaker due to the sun. I am guessing over time it dries out and gets brittle enough to snap. A dash protectant (like Meguiars), tint, and parking out of the sun probably go a long way to preventing it.
At the end of the day it is still a GM design flaw though.
^ +1.
I had a cracked dash on the 2007 Burb I just recently purchased and it was fixed by the Dealer prior to me signing the deal.
To me, a garage does not help a lot as most of us take our vehicles to work where they are parked in the sun ALL day during working hours, where it is the worst/hottest time of the day. (Brutal here in Northern Cali during the summer months).
I put a velour dash mat on my ladies Burb, a perfect match to the dash color. Furthermore, I ask her all the time to put her windshield visors up to keep the sun from beating on the Interior of the truck.
In my opinion, it is not only the heat which is causing the issue, it is also the UV rays from the sun that make the dash materials weak in order to crack.
However, I COMPLETELY AGREE, I think it is a design flaw, as I do not have any, nor have I ever heard of any problems on the OBS or NBS Trucks.