Hempy
The organisers have no power of authority for persons outside the wire. Unless there is a by-law or land owner complaining of trespass, the police have no power either. Common sense and the law are not always in sync.
What is known in the spotter fraternity as a 'naughty field' often places the public in areas forbidden by CAA and MAA regulations yet removal of offenders is not legally viable.
Yeovilton have been proactive in introducing temporary by laws closing bridleways and footpaths, but frankly all this will do is put the stn in good light in a Coroners Court inquiry. The first such court could see the end of air shows in the UK.
..... and had that F16 undershot and taken out even one spectator, the prophesy of doom would be this mornings headlines.