In reply to UKC Articles: Video at 02:16. Look carefully at the nature of the 'constriction' (remember that this is a demonstration for a bomber piece of gear - rated: it should be 5 out of 5 - where 5 is bomber...)
All the forces are acting on a small area of rock which, unfortunately, is unsupported as the crack flares out below the placement. Rated as a 5? No way. Blow the 'lip' of the crack and the placement is gone. "Really good placement" - no.
Next concern - too easy to lift the wire out. Video at 03:09 - I've seen placements similar to this pull out under a fall/loading situation or with rope drag, especially with single rope technique where runners often need to be extended further.
My argument is that if the nut is properly seated - a 5 out of 5 - it shouldn't move if the carabiner moves above the placement because it's the wire which should flex with the rope movement...rather than the nut moving out of its placement. The demonstration relies on the nut rotating out of its position with an upwards tug...