This doesn't make sense to me. It seems like the bartack/knot would be just as likely to jam into the thumb stud with a single loop of cord/sling as with a doubled loop. Right? I mean, either way, the sling is free to rotate and could end up with the knot at the stud. As long as you are conscientious of where the knot is when you extend, it seems like it would be fine to me. BD's just on that resling hustle.