Wasn't wearing a helmet one of the reasons why Mira Leung had a such a weird technique on her jumps?
Once you start jumping and spinning I think a helmet is more of a hinderance, not least from a point of view of straps gettingin the way of your vision. Actually that could apply once you actually get moving and can skate backwards and forwards.
You don't want someone to become relient on a crutch that they can't do without when put on the spot.
Ant