I've heard lots of stories about people falling, witnessed a couple, and had a couple of my own. Though I'm sure it's happened I've never seen or heard of a serious injury.

To put it in perspective, I've wiped out walking on ice more times in the last couple of years than I have fallen due to clipless pedals. I might have even fallen once or twice in that time frame because I tripped over something.

What can you say? Gravity has its downsides.