In the days when it was not an issue, once flew with a Captain who refused a request to visit the flight deck, No, he said, this is my office, if I walked into the bank and flipped the flap in the counter and said I'm just going to watch the Manager at work in his office, they'd fling me out on my ear, or worse. We only let people up here when we're not busy, so they see us sat here apparently doing nothing and wonder why we're paid what we are, keep 'em guessing, the mystery helps the Bull**** Baffles Brains philsophy.
On the other side.... I've met some interesting guests, including minor Royalty, Film and TV stars and the like, and received a few nice "presents" in return ! Sad that it all had to end.
I remember one young lad being asked if he would like to sit in the pilot's seat ? Ooh! yes please, he replied as he grabbed a fistfull of throttles to lever himself up. Three pairs of hands immediately disabused him of that idea !