Slightly off topic, but the northern borders are still wide open.
Reminds me of a case back in the early '80's, a young pilot from Melbourne travelled to Cairns, hired a Piper Arrow from the Nth Queensland Aero Club, and flew to Horn Island, refuelled then popped accross to Daru to pick up some mates of his who were UK citizens not wanting to leave Aus. They left Aus flew to Port Moresby then to Daru. Waited for the Arrow to arrive to smuggle them back into Aus.
All came unstuck when Customs or Police were holding a training session that day at Daru....
Nth Qld Aero Club had to fly to PNG to retrieve their aircraft.
The same pilot was later accused but not charged with flying under West Gate bridge in Melbourne.