Let me clarify. I'm a High Ropes Course instructor and I assist young people and adults enjoy the thrill of climbing, and walking or standing, on poles or trees about 30-60 feet above ground. In all the high activities you are secured with safety ropes which are managed by your instructor on the ground. But being on top of a 30' pole with nothing to hold on to does evoke fear - irrational fear.
People know they are safe yet feel nervous or downright scared and exposed.
Because the fear evoked by the unfamiliar height and exposure bypasses or ignores any attempts to be 'sensible' and rational just as it does in the case of a phobia. For the most part young people tend to welcome or enjoy irrational fear and the adrenaline it produces. Adults are paralysed by it. Act or Freeze Young people keep moving - adults paralyse themselves with fear. Young people give most attention to the physical sensations adults pay most attention to their over-activated imagination.