I have been loving to sit in the flight deck since I was a child. It worked almost always. Last cockpit visit was an 9/14 VIE-KUL. Still dont know how I managed to asked them three days after, but I figured it would be the last chance for a very long time.
On the way back 9/18, inspired by the success some days ago, I asked again and got only blank stares and a very unpleasant conversation with the CSD.
After that I somewhat reduced my requests, all of which were politely declined. Only once on Concorde, I was invited, but only on the ground.