The answer IMO is using two prusik friction hitches. Easy to slide along the cable by hand when slack, but holds you in place via friction when taut (i.e when y

The answer IMO is using two prusik friction hitches. Easy to slide along the cable by hand when slack, but holds you in place via friction when taut (i.e when you slip). Of course these would be a pain to tie and untie at each anchor point