Even no more cases outside Auckland for the following days is no guarantee that alert level 3 will kick in for non-Aucklanders from Saturday.
Prime Minister Jacinda Ardern needs more certainty about whether anyone who's been to a potential super-spreader event might be carrying Delta somewhere such as the South Island.
The current lack of certainty is related to how Delta has changed the Government's response, and how stretched health services have understandably become.
Previous outbreaks have seen fewer people needing to be classified as contacts, which allowed daily updates on how many of them had tested negative, and if any were still being sought.
With Delta, the net for contacts is far wider because the variant is so much more transmissible, so everyone at certain locations of interest are automatically being told they are contacts.
That has seen an explosion in numbers - more than 14,000 contacts, and more than 300 locations of interest - which has put pressure on health services.
Some people who were at locations of interest, having waited all day in line, have been turned away from testing sites that were closing for the day.
Labs have also been so pressed that some testing samples have been lost, while others have been transferred to other sites for processing - two days after being taken.
Another consequence of the huge workload is the level of visibility - or lack thereof - on the people who were at riskier locations of interest.
There were, for instance, hundreds of people at the Assembly of God service in Mangere two Sundays ago, and at least three cases in Wellington had attended the service.
Health boss Ashley Bloomfield said some of the new cases yesterday had also attended the service, but couldn't say how many.
He would ideally know that, as well as how many were at the service, whether any are now in the South Island, how many are still awaiting test results, and how many are yet to be contacted.
Not knowing carries a risk that someone who went to the service is not on the ministry's radar, and they might unknowingly have taken Delta to a different part of the country.
They might even have been in the community if they're an essential worker.
The service is the only event so far that Bloomfield has identified where transmission has occurred - though seven AUT students have now also tested positive - but we are still awaiting test results from more than half of the 14,000 contacts.
So take those same questions and apply them to other major venues - the SkyCity casino, or several schools - where transmission cannot yet be ruled out.
Work has been urgently under way to answer these questions, but it wasn't until yesterday that Ardern could say how many contacts - at least 120 - were down south, and where they were including Invercargill, Queenstown, Timaru, Dunedin, Christchurch, Greymouth and Nelson.
Meanwhile, Aucklanders will have expected level 4 to last until at least the end of the month, with Bloomfield having previously recommended it.
But things are looking rosier for Wellington, where all the eight cases have been linked, and only one has been in the community during their infectious period.
Pushing the next D-Day to Friday also enables Ardern to see if the lockdown has worked, and whether daily case numbers are starting to tail off.
It may also give enough time for any cases to come through that were transmitted in the community after lockdown had started.
There's no evidence of this so far, but any sign of it would be alarming: it's why case numbers in New South Wales continue to bloom.