In the years in which the ASIC requirements have been in force, I can count on the fingers of one finger the number of times I've been asked for my ASIC on arrival at Canberra. And I've arrived in Canberra many, many times.
There's a very easy way to get into a security controlled aerodrome without an ASIC: Fly there.
ATC doesn't know whether the pilot of an aircraft inbound to e.g. Canberra holds a current ASIC. ATC doesn't know whether the pilot of an aircraft inbound to e.g. Canberra holds a pilot licence. ATC doesn't know who or what is on board an aircraft inbound to e.g. Canberra. And someone with malignant intent isn't about to land at e.g. Canberra then twiddle their thumbs waiting for security to turn up and ask to see an ASIC.
The front door is wide open and even includes a welcome in the form of an inbound clearance.