I don't know if it has already been mentioned as I lost patience with the drivel after page 3 but there are circumstances where such an incident can happen.
I recall an internet article by John Deakin where he 'fessed up to almost landing a 744 wheels up at San Francisco. He described the whole approach and how everyone one on the flight deck (there were supernummary crew on board) missed the one little item on the checklist. It makes an interesting read. Can't be fecked providing a link.