I had just purchased a new set of polycarbonate lenses, and was teaching at the police academy. A piece of jacket, or bullet, came back off a target while I was watching the student (not the targets) and struck the left lens just about where I would look through it to see sights on a pistol. It left a really wicked looking circular burst type pattern...As I had only had the lenses 24 hours, the lens was replaced free...but it sure convinced me to always wear eye protection.
So far, in about 25 years, I have been hit in the glasses, side of the face, leg, and of course the ass (about 30 yards from the targets talking). Every time I have been hit was when people were shooting steel.