CDN ATC
Highly difficult to get fam flights within Canada. I have a good friend who is a B767 captain with Air Canada. He arranged with Air Canada a fam flight for me on a trip he was flying. NAV Canada gave permission, my ID was accepted and Air Canada were happy....then at the last minute Transport Canada stepped in and said no it was unacceptable!
I found this quite unbelievable especially as the airline had said it was fine AND I was being personally vouched for by the captain and had a genuine interest in being in the jumpseat as I work at YYZ. You'd think Transport Canada would be the last ones who would have a problem given the level of security clearance I had!
It really is beneficial for both parties, and I have learned a lot on the lucky times (in the UK) I was in the cockpit.