The guilty parties have put up their hands and admitted to H-bombing six bollards in the Town Basin.
Glenda Ferguson and Heather Carthew also admit to being "geri-rebels", their senior years not stopping them having a great time last Wednesday giving the bollards outside The Bach an unauthorised Hundertwasser-themed makeover.
"Glenda and I were naughty, we did it on our own ," Ms Carthew said. "The rest of the The Bach committee were not aware we were going to do it, but we did ask the building's other tenant as it affects them too, and we got a quiet thumbs up."
Two days later, after being politely asked by the Whangarei District Council's property management department, the pair repainted the bollards bottle green - but not before their #hflash style street art-come-activism went "ballistic" on social media, Ms Carthew said.
Complying with the property department's request, the couple purchased the council-recommended paint and repainted the bollards bottle green. "But," Ms Carthew said, "that paint doesn't seem to want to stick."
Sure to have more sticking power, however, is the pro-Hundertwasser pop-up shop opened in James St yesterday.
Hundertwasser HQ is part of the Prosper Northland Trust's publicity machine to ensure the public is well informed before the March referendum the council has called for to decide the plan's fate. The Hundertwasser proposal mooted in 1990 has now come back to haunt four mayors.
The proposal was made when a group of local artists asked Far North resident Friedensreich Hundertwasser to design a Whangarei Art Museum to house the district's significant - but at that time homeless - art collection, and to serve as a visitor destination.
Then and subsequent councils could not muster full backing for the plan.
But adding weight to current Mayor Sheryl Mai's support for its resurrection, three recent past mayors - Stan Semenoff, Morris Cutforth and Pamela Peters - were on hand yesterday to help open Hundertwasser HQ.
The Vienna-based Hundertwasser Foundation's model of the planned art centre is displayed at the site, along with the plans, documents, images of Hundertwasser art works, and merchandise for sale to help fund the campaign.