In reply to John Blab:
The Aiguille du Midi Arete is unique as it is descended after jumping on a telepherique. Normally to get onto terrain like the Midi Arete we (the aplinists) would already be moving together, and would continue to do so.
Given the artificial approach i dont see why parties need a rope to descend, because everybody should be able to use their axe and crampons effectively to descend a very straight forward ridge. Having said this i dont see why a group would stop prior to ascending the ridge and untie from the rope just for this section.
The problem is that rapid artificial access to high mountains and mountaineering just dont mix !