I've wiped out a couple of pairs of pants while glissading (the version of sliding on your butt when descending from a mountain peak). It's darned embarrassing to stand up and your undies are exposed to the world! (Good thing I had a pair of windpants to wear the rest of the way, and had to walk or standing glissade--you don't want to sit and slide in windpants or you'll go out of control very quickly).