The BA announcement on switching off needs to be revised then, as it is ambiguous and those of us who have heard it many times still may be interpreting it wrongly. Occasional flyers will have no chance then. It should say that you should switch to flight safe AND THEN switch off completely, if that's what is intended. Still, no headphones allowed, and I always switch my laptop wifi and bluetooth off prior to departure but I always then just put it into hibernate.