I'm a 35-year climber and have no problem with single line climbing, but...
I know a fellow that cratered because the head pulley broke, dropping the halyard on a sharp edge and cutting it through.
The problems is that you DON"T know the quality of the gear until you get up there. It's not like climbing gear that is inspected with every use and stored out of the sun.
Not sayin' you can't climb a single line, just sayin' you're guessing and the the folks using a safety line have reasons.
I know a fellow that cratered because the head pulley broke, dropping the halyard on a sharp edge and cutting it through.
The problems is that you DON"T know the quality of the gear until you get up there. It's not like climbing gear that is inspected with every use and stored out of the sun.
Not sayin' you can't climb a single line, just sayin' you're guessing and the the folks using a safety line have reasons.