Mate, let's put an end to this nonsense.
Make your own choice.
If you have enough common sense, you will know when to wear a lid.
If u don't (have enough common sense) then please stop kiting!
Think.
Packed sand may not split your nut but what if you get dumped in mid air and fall stupidly onto your own board with your nut hitting the board!
If ur not doing air but just sailing up an down the beach, u probably don't need a lid but it doesn't hurt to wear one does it just incase.
And then u don't know what's lurking just beneath the surface of packed sand do you? Go down the beach one day and there's rocks everywhere, go the next and they're gone but are they? Sand covers rocks too and if your unlucky (which sod's law usually takes care of) you might just fall on a bit of sand that has a nice rock just cm's underneath!
The wind can do strange things too, afterall it is a body of it's own. Look at the kitesurfer that got thrown onto his own house roof the other day! he was about 4 foot in the air doing a trick and a sudden gust just hurled him way into the air, over some trees and dumped him on his own beach house roof!
It's probably rare but it can happen!
know yourself, and when u think u should wear a lid - do it.
And most of all, if u crack ur nut cause u didn't wear a lid, don't come crying here!
P.s. page 100 in the latest kitesurf magazine has a good article explaining just why u should keep ur hat on!