Regarding getting the wimbles if you are up high, it apparently works the other way in parachute training. The squaddies are made to jump from a tethered balloon, which is all of 200 feet or so, and absolutely terrifying. I jumped (wan't pushed) out of a perfectly servicable airplane at 2,000, all by myself: the chute ripcord was attached to the aircraft, so any sack of potatoes could have done it. For some reason, it seemed like a reasonable thing to do, but I am very very scared of cliffs, ladders, roofs, edges in general.....