Bill Cohn's story is correct...
I remember the story, he was generally on flights "based" at JFK
, goes back around 1970, I was then based in Berlin with the IGS 727s...
We did not have an ID
tagged on our uniforms in these days, not subject to any security, metal detectors. PanAm was a big operation, we had crews based at various locations within the US and overseas (Europe), and often flew with crews which were temporarily based with us, but actually were from other locations, hardly knowing most of the crew we were with.
I assume that Bill Cohn was probably knowledgeable about F/A cabin service and procedures, he was probably acquainted by another PanAm F/A - a friend maybe - about what to do, to appear to be a legitimate crewmember...
ex PanAm 1969 - 1991