If that miserable excuse for a politician running QLD bothered to look at the almost zero infection rate in the vast majority of both QLD and NSW, and then applied some accepted risk management strategies that businesses use every day, there is no reason why cross border traffic between those zero infection areas should not occur.
Once again, COVID -19 is all about risk management strategies, not blanket policies that lock the joint up.
I won't go into the detail here obviously, but there are ways of getting in and out of QLD by air without attracting attention. Anyone desperate to do so will be able to work out how.