When you're at a fairly low standard its not so bad, but once things start getting bigger you have a long way to fall usually. If you look at anyone gapping (for ease, look at the Damon Watson video 7 on't vids page) they put so much effort into the pedals that if the chain snaps, all your force is going in to sending you flipping over the bars. If you're dropping off something, you go face first into the ground, if gapping up to front you go face first into the ledge you're going up to, etc. Really ain't a good thing. Always hit your bollocks too