So, my question is: has anybody who actually rides mountain bike with
any frequency (such as the amb crowd) experienced this phenomenon or
heard of anybody loosing a wheel? If so, any serious injuries? Is
the sky really falling or can we get back on our bikes and ride?

I would like to offer the first response to this question. I think the QR
scare is ********. A simple look at ratios can tell you that out of the
millions of riders with the disc brake/QR setup, there are only one or two
documented cases of it happening. Crashes happen every day due to equipment
failure and rider error... moreso the latter. There's nothing to get
excited about here, folks.

-John Morgan