So I am to believe that you have never watched an airshow or other airplane activities from outside an airport before ?
I've been to both sides of the fence, and a regular at Duxford normal days as I have an annual pass. During airshows, most of the people I saw in the past in the fields were photography enthusiasts, they wanted to get those perfect flying shots. The light from the south side is perfect, inside Duxford its in your face. The view was perfect and unrestricted, inside Duxford most of the crowd line is taken by enclosures of this club or that association etc etc. The crowd line access left for the rest of the public is lapped up within the first few minutes by those that park their camp chairs and 'reserve' their space for the rest of the day, so anyone wanting to do some serious photos can forget it because they cannot get anywhere near the crowd line. Lets not mention the fact that on Sunday, apart from the steep entrance fee (which is due to go up), and all the extras inside, they were also charging for the car park (which I hope does not become a new trend), and also only by pre-booking, no tickets at the gate (also another growing annoying trend). Tough luck if anyone decides to go with you last minute.
The reason the prices have gone up is I believe entirely down to increased insurance costs for after the Shoreham accident, and lets not forget some of those who died in the accident were there to watch the show from outside the field. The whole point of closing roads and "naughty" fields is to stop this ever happening again