Im not looking for an argument but pointing out a plain simple statement. Turning the fuel valve off in flight is absolutely as safe as pulling mixture period.
This is not trying to **** stir, but I know of a number of Partenavia operators who don't want the fuel taps manipulated due to wear and possibility of failure (even x-feed checks during taxiing. They say 100 hrly cx were sufficient). Any LAMEs care to comment??