Thanks for all your response guys.
Some interesting theories but Spit 15 wins. By the way Dan Winterland, I always thought that the gauze was there to reduce fraying and prolong the life of the sock.
Still, some interesting theories. It is NOT a CQB question from the ATPL, (although if a certain ex-colleague now at FCL sees it, it may well be added!). It is simply one that was presented to me in my days at the RAF Central Flying School, and it's obvious that some of you ex-PPSC guys have heard me ask it before.
Well, after all, it helps to keep a little scientific thinking going on the site.....
Aye, David