Also, I bet that the pilots wouldn't dream of making the short hop across from Dover to Cap Gris Nez on a hot sunny day without, at the very least, a couple of lifejackets. Very sensible too. They were prepared, however, to plan and fly a route over some of the most dangerous terrain in northern Europe, terrain which regularly kills even experienced and well equipped climbers and walkers, in winter, without any outdoor gear, emergency kit etc.