Working at an outdoor school which teaches climbing, I have had to, numerous times, rap down to check the anchor (not my favorite thing to do) or check for bee's nests and other critters. I have found a method that works for me. I take a sewn sling and make an auto-block knot below my tuber. I clip the knot on to the biner that my tuber is clipped to. I then downclimb (gulp) and end up so that my weight is on the anchor. I then rap down safely. I have found that lighter people need to push the autoblo
ck knot down as they go. Sure the knot does make for a much slower ride, but it is much safer than just simply clipping in and jumping.