Can't answer the question posed in the opener but as a Trainee Crewing Assistant (wanabee pilot) with Caledonian in 1966, I was SLF in the back of the company DC7 outa Jordan, for fun on my days off. Anyway, inbound ops crew were deadheading back to Gatters. Outbound crew, we were told, had their uniforms stolen from the hotel during previous nightstop. They sat with pax, in civvies. Lots of trolling as they mumbled things like ;"Why are we waiting...Where the hell are the pilots...." etc, when Capt stood up, loudly exclaimed," Oh, had enough of this, You (points at Flt Eng) and You (points at SFO) come with me !". The three, all in civies, walked up to the FD, closed doors and soon after first of the big props started bursting into life. Magic.