Was out mountain biking on the trail Tuesday night. Came around the corner on the trail where another guy had just wiped out. He had just his bike shorts on and no mountain bike shorts over them. Left butt cheek of his shorts was tore all the way through from the crash and you could see skin and he was bleeding.

This is why you wear mountain bike shorts over the padded shorts. It's not a fashion thing or an elitist thing it's called common sense because the likelihood of crashing while mountain biking is much higher than road riding.