That's a reasonable use of the leash. I do "basically" the same thing with a spare kite leash.

If you do use a leash (while riding), wearing a helmet is agreed as being wise.

Oh... there is ZERO need to wear a leash while land launching a kite!!

http://www.youkiteboard.com/view_vid...7c996a5ee53a70

The vid quality sucks, but this is pretty dumb. Is it SO windy he is afraid his board will fly away while launching?