People who work at heights usually have just enough fear of heights to not do something stupid. Those with no fear of heights tend to make fatal mistakes.
Source: 35 years of climbing and 10 years of industrial rope access :-)
To quote Jim Whitaker, once upon a time a famous climber and founder of a well known mountain guide company, "If you're not afraid of heights, I don't want to be on the mountain with you".
Hi, I've considered changing careers to rope access or similar for a while now. Can I interview you about your job? Please email me, see profile. (This request extends to other RATs reading this too!)
No problem, I've sent you an email.
I'd say their balls have a relative density in between bromine and tungsten. Uranium = customer service roles.