I'm not a big fan of the event, and it is a slap in the face for Australians either "stuck" overseas or merely wanting to come home to visit family. But, can we dispense with the hysteria, please?
There was until recently a 6000 person cap a week for Australians coming home, so during the month of December it is entirely plausible that as many as 24,000 travellers arrived on Australian shores (including the author of this post) that could have "reintroduced covid". And even with reduced caps since the second week of January, it is still possible within the revised caps for 18,000 travellers (plus the AO contingent) to arrive in Australia this month. Yes, I get the hypocrisy about allowing in spoilt brats to hit a ball around court, but 1200 represents about 6% of total intake for the month, and this particular cohort will get tested more than the other 94% - both before and during their quarantine period. I'd say the risk is increased, but not quite as significantly as many make out.