I found out today that a friend of mine fell 'about 20 feet' when the line slipped. The helper had had him up there a hundred times before but this time was different in that the line slipped. This follows on the heels of my former rigger's fall from the masthead. She will be in rehab for a ling time as will my friend. Both are incredibly fortunate to have no paralysis nor brain injury although you can imagine both are pretty broken up. So, hook on a safety line even if it's a quick trip! I don't do it but sure will.