once when I was up on Mt Washington and getting ready to rock and roll in the winds, there was *one* clasp on a strap on my backpack I didn't close, and when I turned it hit me in the side of the head right next to my left eye. Left a nice bruise, but that was it. Winds were only 50 ish mph that
Edit: one day in the winter on Mt Wash I was next to a group being guided up by an Eastern Mountain Sports guide, and at the bottom of the Alpine Garden, right where the winds will get gnarly, he was yelling at them above the wind "OK! Every single piece of gear you have, buckle, tie or clasp everything on it NOW, because if you don't, it's a hazard"