Ah, a thumbs-down at the beginning of the post again; it can mean only one thing.
Actually Lu, you're not often right but you're wrong this time. The only people in the audience who'd be lost would be those who can't/won't listen - sound familiar?. None of the exchange QHIs we've had from the States over here (some of whom have been good enough to win the theory and flying prizes, I might add) have had any difficulty grasping the concepts so clearly stated here and elsewhere.