Sorry to say, but I have to support the ban. Speaking with your head twisted around for so long to people when you are travelling at up to 600mph with up to 400 people with you is not such a good idea. I have had people wanting to 'bring their son up for a look' and appear with a babe in arms, and with a full nappy at that, I have had people up who you suddenly realise are inebriated, or just bored. We once had several visitors on the flight deck with both us pilots twisted around talking when I heard a very soft sound. Took a few seconds in all the talking to identify the noise as like a 747 engine surge. I turned around to see the exhaust gas temperature quietly winding up and closed the thrust lever and had to shut it down. I'm afraid it has gone for good, and I can't say I'm sorry. It's a shame genuine enthusiasts can no longer come up, but too many people have abused the privilege. It's too much of a distraction.