What you've described is what a lot of canyon leaders do - ensure everyone goes down on independent strands; then put the leader at risk by undoing the knot (by "at risk" I mean only in comparisson to the punters - every other canyoneer wouldn't bother with the knot.)
As per simul-sailing - you would generally abseil much slower; which negates your issue of beating benightment.
Who draws the short straw, getting stuck at the top, in the dark, untying heavily weighted knots? |