I went last year. Once he's through the gates, no-one will pay him a blind bit of notice. There's a separate tent for her Maj, which he is unlikely to be invited to, and others who she greets are chosen at the last minute by courtiers and equerries, who have a quick chat to make sure she's not about to meet a nutter. Last year, there was a huge thunderstorm and huge hail fell, and it all got a bit muddled, with everybody being invited into the nearest shelter, so plenty ended up in the royal and diplomatic tents who might not have been otherwise. Brenda was shuttled back inside in a Landy, and lots of us got to see various bits of the palace we weren't expecting. They don't allow you to take your own cameras in either. Very nice cake btw.