But don't forget that at your hypothetical aerodrome, there would be imaginary lines delineating a secure area that the huge wall etc is protecting, Anyone who flies in from unscreened ports, or who climbs over or cuts their way through the adjacent sheep fence is prevented from crossing these imaginary lines by a wizard with a staff and a lot of signs that say
"You shall not pass!!, unless of course, that person wears a sacred ASIC. Even if in possession of a sacred ASIC, the person will still need to go and submit themelves to the scrutiny of the gatekeepers at the portals of your great wall. Only if judged pure will they be allowed access to the hallowed Secure Area.
So you see that Aviation Security in Australia, using rigorous, well thought out procedures, and magic, works even at your hypothetical aerodrome. There is nothing to worry about
