Here's how I see it IMHO
Beginners, fall hard because they are too busy skiing to notice that a fall is occurring, so when they realize it they tend to over react to the fall. (Fear and slow to react)
Intermediates (aggressive ones), tend to think that they are a lot better than they really are (this is to do with the great equipment that is now available), so when they crash it tends to be hard. (Fear and too fast react)
Intermediates (moderate ones), tend not to crash as caution tends to lead the way, but when they do they tend to get caught off guard. (Fear and slow to react)
- Tend not to get caught off guard by an error so when a crash in the offing, tend to respond for the quickest recovery. (Not happy, reacting correctly)
- When caught of guard, also tend to respond for the quickest recovery. (Definitely not happy, but reacting correctly)
- When its a truly unexpected/or hard crash despite everything, they will fight it all the way while going down in flames. (Oh Crap, hope this works and doesn't hurt too much!)
The best thing is knowing when to relax and when not too. Its not about knowing how to protect oneself, but more of understanding that it is about to happen and not being fearful of it so that you can relax through the fall and not accelerate the crash.
My feeling is that this something that could be taught at the beginning as the art of crashing, the more a skier understands it, the great the chance of reduced injury.