Not too sure why there was so much confusion in these threads really. Years back in my instructing vintage the "Bona Fide" bit was taken as that. Been utilizing that rule for years. What is more Bona Fide that teaching someone how to survive when the donkey gives up the ghost? Too many instructors are worried about the Joe Public's who have nothing better to do than complain than about teaching somebody how to handle an aeroplane properly.