This happened to me once on a trip to LHR. I went forward to the flight deck and spend quite some time chatting. We discovered that we had mutual friends in the Air Force. The captain asked for my business card and I later received a note acknowledging my visit to the front. I had forgotten the incident and your post jogged my memory. I presume that I got the note because of our good mutual friend. It is the only time that I received such a note after many visits to the flight deck. I used to be in the Air Force...