Forgive this thread creep, but can't resist sharing - if you havn't seen the film "The Russians are coming, the Russians are coming" it is a classic and well worth watching.
The relevance to this discussion of evacuation takes place when the Soviet submarine crew are attempting to steal a motor yacht to tow their sub off an inconvenient sandbar. They invade a dry cleaners and cover their uniforms with incongruous civilian items, then proceed toward the docks telling everyone they meet - in heavy Russian accents -
"Emergency! Everybody to leave the street!"
When I am briefing a passenger in my glider, I first fit him with a parachute, and tell him- "If I say to you 'bale out!' don't turn around to ask me what did I say, because I won't be there any more!.....you can then decide what to do next.