That video wasted so much of my time.

Board leash
 

When I was learning to kite and still used a board leash, I had the board fly over my head and go through the lines near the depower strap! Over powered and scared shitless!! I haven't used one since. I have lost my board in big surf a few times, I relaunched - body dragged or swam into shore and was able to spot the board and then just body dragged or swam back out to it.
Tips from humble Dean
-Scripto your name, email,etc on your board
-If you do use a leash/helmet, use a velcro connection and only connect an inch or less. This way it will disconnect before it flies at your head!