Thanks for the replies.
It was as I suspected although it never seemed so bad before 9/11 (obviously!) I feel for the crew who could get charged with gross misconduct even if the cockpit visitor had all the ID needed. Jumpy passengers I can appreciate...I have sat next to enough of them!
NATS used to run a BA course after you had completed training which involved two fam flights on European sectors. Not sure if they still do this. I also believe when travelling standby if you are a pilot or controller you can get offered the jump seat..I may be wrong on that. I sat behind the crew once on a Twin Otter flight from Glasgow to Barra and listened intently as the pilots did all their checks and the like...then asked me to describe the women on board the plane for them.....Ahh those days of low security!