It will still happen in a climbing harness if you are hanging in space. On a hanging belay, you try to get your weight off the harness and get your weight on yo

It will still happen in a climbing harness if you are hanging in space. On a hanging belay, you try to get your weight off the harness and get your weight on your feet on the wall as much as possible. This alleviates the problem. Cavers will spend a long time hanging in space on rope when climbing out of deep pits (over 100 meters / 300 ft) with single rope technique. That doesn't lead to harness hang, because you are engaged in aerobic activity with your legs.