I ride an aluminum bike with a carbon fork. Neither has failed, but I've not been in a wreck with it. The question here is how many people that have been in the same kind of accident have experienced the same kind of damage? Is that type of damage only experienced with no-name Chinese frames, or do people on Cannondales, Treks, Specialized, etc. also have that happen? I'd probably disregard the anecdotes from anyone who hasn't experienced the same type of accident. On the other hand, if your bike folded into pieces like that while you were going 15 on a flat and hit a shallow pothole, I'd say it's definitely the frame.