I was on a Virgin A340-600 a few months ago and asked the cabin crew if they would speak to the Captain regarding a quick flight deck visit on the ground at the other end.
They got back to me and said that the Captain would be happy to see me when we landed.
But when I went up there to take a look a rather stern German/Austrian FO said I could only visit if I had an airside ID?
He must have had a long flight...