On the other hand...
Flew to jo'burg from LHR last week and passed on my immaculate letter (with appropriate photocopied sheet from my logbook) to the cabin crew on boarding.
Wasnt allowed jump seat.
Subsequently disposed of the letter.
On the return leg, politely asked to speak to the captain during the cruise. After a few hours of interesting conversation, was invited back to watch the landing into heathrow.
I guess it all depends on the Captain (or the quality of your letter!!).