I did get one top pro to comment. He said that he figured most pros shoot some kind of a loop. If for no other reason than that the serving wear is down. He says he gets better than a year out of each string and serving combo.

This also explained my finding that there wan't much need for it. I shoot a lot, but I sure don't put the wear on a bow a top pro would, and I don't shoot much in the winter. So wear isn't a big deal.