Yesterday I was doing a downwinder. Half way down there were some great waves (about 2 to 3 meters high). In one of them I crashed and when I came up to catch some air - Bang, and the board hit my head. A clear cut and blood running down.
I kited home and when I came out of the water and other kiters looked at me, asking what happened, everyone of them told me it had happened to them in the past too. I was amazed...
But there is nothing you can do other than be careful and to be prepared that the board might hit you (and no, I don't want to start a new helmet discussion).
PS: When I came home from dinner and we had a last drink at our friend's apartment, I showed them something on their TV. When I went up - Bang, and this time a cut and blood running off my forehead...you can imagine the laugh. It was definitely not my day yesterday!