This is from Snopes.com:
Claim: The purpose of the 'crash' or 'brace' position is to kill passengers quickly in the event of an airliner crash, or to preserve their remains so as to make identification of bodies easier.
They go on to explain that the "crash" position can actually save lives and that 71% of airplane crashes are survivable.
I just wanted to say that I really wouldn't want to survive an airplane crash where I was one of a few survivors. Think about it. You will probably need 25 years of rehabilitative therapy just to learn to walk again, and you will spend the rest of that time being spoon fed jello and going to the bathroom into a cathater. Is that really living??
So I've decided that if I'm on a commercial airline and they say over the loud speaker, "Hey everyone assume the crash position, we are going down!!", the first thing I would do is snap my own neck. You want to wait til impact? Go for it! I will go down with everyone else but my soul will already be in heaven. See ya there suckers!
With my luck the headline the next day would read..."Crashing Plane Lands Safely: Idiot On Board Snaps His Own Neck"