This year, for the very first time, not a single National Party MP turned up.
Even in February of 2018, just three months after NZ First cast National into Opposition, a few National MPs turned up, including Steven Joyce and Todd Muller.
The stalwarts have been Alfred Ngaro and Mark Mitchell.
The National MPs' presence had always been taken as a sign the lines of communication between NZ First and National were not totally closed – that there were people who could salvage it when the time came.
Another one of that handful of MPs keeping that door open was Todd McClay, who is relatively close to Peters.
The reason for the Nats no-show had come two days earlier, with National Party leader Simon Bridges ruling out dealing with NZ First after the election.
Several National MPs have insisted there was no directive or discussion about whether they would attend.
In fact, some said it was pure happenstance that every single National MP got caught up with other engagements – from a barbecue at Andrew Bayly's to a catch-up with some iwi leaders.
But for any National MPs to attend the party would not only have been a bit awkward – it would have given some credence to NZ First leader Winston Peters' line of defence.
He had claimed that if NZ First was the kingmaker in 2020 and Bridges did not pick up the phone, some of his other MPs would.
Bridges and Peters met face to face two days after Bridges handed down his decree.
That was at the powhiri for the politicians at the Waitangi Treaty grounds on the morning of Jones' party.
There is a video of a critical point of the powhiri circulating online. It is a mélange of power plays.
It shows Green Party co-leader James Shaw, having accepted the wero, waiting for the rest of the group behind him to catch up.
Ardern is walking next to Peters, who is next to Bridges. Bridges has his chin jut on. Ardern has her "solemn occasions face" on.
Ardern is looking at Shaw, mutters something and gestures with her hand. Peters then mutters something, grabs Shaw and almost yanks him over to the slot between himself and Bridges.
It is possibly just that Peters needed Shaw out of the way because he was next up to go forward to accept the challenge.
But many saw it as a bid by Peters to separate himself from Bridges.
The more likely explanation is that he did not want Shaw to end up next to the PM.
Peters has always been obsessed about keeping the Greens in their place as mere confidence and support partners rather than full-blown coalition partners.
And as Peters deals with questions about his party's funding and his stoush with Bridges, the more he is seen being tacitly endorsed by the PM the better.
That "endorsement" could be critical in one electorate: Northland.
Bridges' call to cut out Peters may have decreased NZ First's chances of getting to the 5 per cent threshold, but it will also have increased the chances of NZ First taking back Northland.
That electorate is now shaping up to be the most critical of the election campaign. Shane Jones is expected to stand for NZ First – and it may end up being the party's lifeline if it cannot gain the 5 per cent threshold.
The 2017 election showed that about one third of Labour Party supporters split their vote and supported Peters as the Northland candidate. That was about 4,150 votes.
Almost 20 per cent of National Party supporters did the same – about 3600 voters.
Those National supporters are unlikely to do that again – but if more Labour voters do then Northland MP Matt King's majority of 1,390 will be under threat.
There is now no risk Labour supporters will be giving their votes to somebody who might set up a National government.
That will make them feel more at ease about voting for Jones – especially if National is polling strongly as the election nears.
NZ First may quietly be hoping Labour tells its voters to support Jones for the candidate vote, although Ardern has said she will not be reining in Labour's candidate – Willow Jean Prime.
But there is nothing to stop Labour voters in Northland coming to that conclusion all by themselves.
That is exactly what happened in Epsom the very first time Act won it in 2005.
That took a lot of hard work, door knocking, meetings and persuading by then leader Rodney Hide, but he did it with no help from National.
Poor old Northland will be buffeted for the third time by politicians making desperate promises in a bid to win them over.
If any sign was needed about Jones' intentions, it may be notable that in 2017 and 2018 King was invited to Jones' annual party.
This year, his invitation apparently got lost in the mail.
