I took a tumble last night on a steep climb, went over sideways off the edge, bike followed me and the end of my lockon grip smacked the back of my lid pretty hard…sure the base of my skull wouldn't have enjoyed that!
I always wear one on and off road when riding alone or in a bunch, I'm also pretty vociferous about my clubmates wearing them on the road
BUT if I'm pootling along with the kids/my wife on a smooth cycle path I don't wear one…rating the risk level as low