I wonder what happens when one of your crew tests positive somewhere like Sydney. Long haul carriers are not going to have standby crew members everywhere. The risk of one of your pilots being quarantined or even worse falling ill at a distant outstation is not negligible if mandatory testing is introduced. Identifying non symptomatic aircrew is obviously good for Australia but complicates matters from a crewing point of view. What do you do if the captain tests positive on arrival. Obviously the other crew are high risk. Do you fly a whole new crew in or just a replacement? The whole thing becomes extremely difficult to manage.