Fun video there! Pity Avalon is essentially tree-less so he has nothing to fly around. Props are good for low level like when Matt Hall was below the tree-line at Tyabb airshow. Adds to the suspense as you wonder if he's coming up again!
One can assume the reason for the security is the military kit, however it wouldn't be the same without it. Catch 22.
It would need to be in a capital city to get the volume of visitors. Much of Melbourne has been before and are over it. If it was in Canberra for example perhaps a lot more would attend at least for the first one.