I am sure we all appreciate the federal government's bid to secure Melbourne's borders, but in the aftermath of its farcical Border Force debacle, I have a tactical suggestion. If you really want to catch visa violators, just invite Liverpool FC back to play another match at the MCG, then round up the 90,000 English visa over-stayers who rock up.
In fact, once everyone is in, just lock the stadium's gates and you have yourself a brand new ready-made detention centre.