Hi Josh.
I think Azapa's concern is quite related to low visibility of the waters he is diving in. There he cannot use "trampoline" theory I guess.
Plus - disorientation can be BIG in his conditions - remember your dive to 50+ that day at Molokini when I was your safety diver - we lost each other no matter visibility was almost ten times better than in Azapa's area.
I think that usage of line in his case is necessary (advisable at least) as it was in ours.
