For clarification, in regards to the posting by Carbonsports GmbH. while descending in heavy rain, the wheel delaminated and inner tube exploded. By luck, and the fact I was not going that fast, I was able to come to a complete standstill without the bike ever touching the ground. Therefore no chance the accident caused any damage seen on pics. Based on conversations with friends in the bike industry in Britain, Germany and France, I believe this type of delamination is not that uncommon with the particular type of Lightweight clinchers I rode. Let's hope the My 2013's do not have the same issue. Just to be extra safe however, this summer in the Dolomitis I am riding on alloy wheels.
Riding alloy wheels during long descents, wet or dry is a very good idea. In fact I want alloys during any mountain riding. I just don't see any significant advantage of carbon given the robust construction and relative light weight alloy clinchers available today (eg; Shimano DA C24's). Yes, carbon wheels may carry a few grams less weight but they also carry risks - not the least of which is relative poor braking.
I don't believe any carbon wheel is immune to possible delamination due to the intense spot heating effect and resulting shear forces generated within the composite structure (including any core material like foam). Cores of foam or honeycomb do add structural integrity however, these cores are generally bonded to the laminate and this junction itself is subject to shear forces during heating (see the article posted by Carbonsports above).
It would be nice if Carbonsports provided information on the testing that they subject their wheels to in order for customers to better educated and able to make the decision whether the risks of carbon wheels are worth the staggeringly high price.