Is it the same today? In my day, my CO used to make a point of always having a WO Flt Eng or Loadie on his crew if the trip involved flying into an American base.
Whenever he had any task to complete on the American base, he'd always take his WO Flt Eng along with him - and usually 'meekly' follow one pace behind him.
All the Americans would see was that eagle on the sleeve (that's where they wore their rank back then) and take the WO to be a bird colonel.
All doors would magically open and the service offered could not be faulted.