In reply to myrockface:
We did the approach (ended up on Rochefort arete) in the heat wave year when MB was banned and people were evacuated from the Matterhorn. It was unpleasant, as is basically a shale scramble, rocks were being knocked off by many parties and it was hard to avoid doing the same. If you are up for it, probably be wise to be first up the approach slopes as early as possible. Not much fun coming back down either but parties had dispersed a bit by then.