Reminds me of the thread in the kite forum of the guy with a kid strapped to him.
I personally think this is utter stupidity. We have all experienced that sudden gust, bit of weed etc that has put us over the handle bars. Imagine falling forward onto the boom with a child strapped to you or if you fall and are under the sail.
He is probably only in a few feet of water but I think he is taking unnecesary risks with a child that has no say in what is going on.