Ian Stewart wrote:
Sure, you SHOULD run your rope through rounded metal if at all possible, as many people here have already said, but why are you so vehemently against other techniques that (even you admit) will work fine? I've never rapped directly off slings and wouldn't really like doing it, but if I found myself in a situation where I had to bail and rap off a few pitches without rap rings, I wouldn't think twice about cutting up some webbing/cord and rapping directly off it. Would I want to leave lockers or opposed biners when a few feet of webbing is sufficient? No. Would an engineer spend $100 million to build a bridge when $50 million is sufficient? No. It seems as though you think rapping directly off slings shouldn't even be discussed, but I think it's worth knowing about ALL the possibilities so that you can use all that knowledge for your particular solution. You never know what situation you'll find yourself in, and knowing that rapping directly off a sling is safe could save you from leaving other gear that you may need for something else. Just like I know that girth hitching a sling directly to a nut isn't the most desirable situation, too, but knowing that it's safe enough has helped me avoid other worse situations in the past.