That's an interesting topic - in the old days, when film was at a premium, every frame counted, so preparation was usually meticulous. Lighting, setting, positioning, angles.
These days, for an 'untouched' shoot, do they still make use of digital's ability to shoot a thousand images, selecting even fewer than usual to run as the end result - or do they fall back on any of the older ways to structure the image before the moment of capture?
For a YSL-sponsored cover story for US Bazaar, I'm guessing it was just another day of getting the shoot in the bag, rather than an exercise in anything interesting.