While many will give in to the temptation to focus on what appears to be a classic "foot in mouth" moment, the real message is no jurisdiction can get too confident, or lower its guard, regardless of how good its record is. Past performance, as they say in the superannuation advertisements, is no guarantee of future results.

That was the point NSW Premier Gladys Berejiklian made when asked to respond to Mr Andrews' statement of superiority on Wednesday: "This is not about boasting, it's a fact."

While conceding Mr Andrews was "pretty good at spin", she said the NSW quarantine system wasn't perfect and she would never make such a claim.

"All I know is NSW has welcomed more than half of all the Aussies coming back home when other states have been in lockdown or refused to take people," she said.

Victoria's lockdown, sparked by the escape from hotel quarantine in Melbourne of the highly contagious strain of the disease first identified in Britain, was timely given ACT authorities, who had just welcomed 166 returnees from India into quarantine here, were already reviewing their own arrangements. Following revelations a woman in New Zealand had tested positive for coronavirus even after spending the full 14 days in quarantine, our health officials were already considering mandating further tests on the new arrivals after the end of the isolation period. They had also reacted swiftly to the alarming news the virus may now be out in the community after a positive case completed a shift at the Brunetti cafe in the Melbourne Airport's Terminal 4 on Tuesday.

Almost 10,00 travellers, who passed through the terminal on Tuesday and Wednesday, including 7000 to NSW alone, were potentially exposed. Travellers who arrived in Canberra from Melbourne airport on February 7 and 8 were asked to identify themselves to authorities, get tested and go into isolation until they were cleared. Those who arrived in Canberra after midnight on Friday had to isolate for the full five days of the latest Victorian lockdown.

There were also implications for this week's sitting of the federal Parliament given Victorian MPs only had a few hours' notice to get across the border before the lockdown conditions came into effect. The Prime Minister had to make a hasty retreat on Friday afternoon after travelling to Melbourne for a vaccine announcement at CSL.

This year, as ACT Chief Minister Andrew Barr predicted earlier this year, is starting to look a lot like 2020 - especially for Victorians who were more entitled than most to have a bad case of "iso fatigue".

One immediate consequence of the latest Victorian outbreak and lockdown was the decision for the latest easing of local restrictions, planned for Friday, to be deferred.

While neither NSW or the ACT had formally closed their borders to Victoria, despite snap decisions to do so by many other jurisdictions late last week, this can't be ruled out.

"We will be reviewing our position after monitoring what is happening in Victoria," Mr Barr said.

The hope is that, as was the case in recent outbreaks, Victoria's five-day lockdown would break any chain of transmission and allow the contact tracers to do their jobs.

The alternative, that Victoria finds itself in the grip of yet a third wave of mass community transmissions, is almost too awful to contemplate.