IIRC, wasn't it SOP for a member of Cabin Staff to occupy whichever seat and read the Checklist, in the event of a Flight Deck incapacitation. This was normal and they were trained for it.
Another known factor is that a number of Cabin Staff are trained Commercial Pilots but,for a lack of airline flying experience, are unable to get jobs just yet.
IMHO, why the hell not, particularly on a positioning leg. ?? Great CRM !
