Used to do the flight deck jumpseat a lot when I worked on the ground in a UK airline - never overly inquisitive, but with a private certificate just happy to sit there and watch and listen to the pros do it properly. I guess that to some, my having a private licence makes me more dangerous than the rest these days!
Sadly, United's channel 9 is as close as I get these days - one of the reasons I like that airline! I know it still slightly irks a senior captain friend of mine that he has to let folks from the CAA and the like who he's never met before onto the flight deck from time to time, and yet a friend of 30 years can't visit.
Andy