I can bend in half with my knees up by my ears. I can see someone ripping a hamstring muscle or two in this position, but getting killed?
I mean, unless they can somehow keep their knees PRECISELY together, and PRECISELY aimed at their skull at the moment of impact maybe, but what’s the natural inclination of your legs when forced down, or back as it were in this position? to go to either side of your body, thats what. NOT straight on into the “kill zone” of the nose into the skull. Besides most people sitting in this position are rather ungracefully sprawled with the knees to either side anyway.
Also, like another poster mentioned, I’ve heard of a LOT of weird accidents but NEVER one involving feet on the dashboard and killer airbags.