I used to do a LOT of windsurfing (sponsored by Bic) I only ever had one bad accident on my boards and that was a cracked rib from a impact of being slammed into the water while sailing in Newport RI durring a hurricane.....
You CAN get slammed into the water good on them but ussually it is not something were you get hurt. Plenty of stubbed toes but nothing life threatening. I did wear a life jacket all the time but angering my folks I wore it so that I could wear lead and hold up a bigger sail
If I had a 15 pound boyancy vest I could put about 13 pounds of lead into the pockets. The things we do when we are young
I have NEVER been pulled over by the coast guard or anyone for that matter for not having my life jacket on.
Jon