The case Tamiefuna v R is an appeal against a burglary conviction which was ultimately based on just such evidence: a photograph at a roadside traffic stop, which was not taken for any investigative purpose, but for an "intelligence noting": that a cop thought it might be useful sometime. And the Court is crystal clear that this was a "search" in terms of the BORA, and that "there is a reasonable expectation that a person’s photograph will not be deliberately taken and retained for identification purposes by police without a good law enforcement reason" (a "search" in Aotearoa now includes surveillance where there is a reasonable expectation of privacy). They were also clear that it was illegal:
The police did not act with legal authorisation when they took Mr Tamiefuna’s photograph. Their conduct did not accord with statutory provisions in the Policing Act 2008 and Search and Surveillance Act 2012 in which Parliament has conferred power on the police to take photographs. This specific conferral of powers to take and retain photographs is inconsistent with any suggestion that the police may photograph persons and retain their images without bringing any charge and without any obligation to destroy the images.The latter puts some pretty significant limitations on "third source" activities - they can only be incidental to an investigation, and cannot interfere with liberty or privacy. This means, for example, that a police officer can't just follow someone (interfering with their reasonable expectation of privacy against being followed and having their activities recorded by state agents) without a specific investigative purpose. It probably also limits their ability to infiltrate or spy on public civil society organisations "just because", unless they are investigating a specific crime. And the police are not going to like hat one bit.[...]
[T]he police could not rely on the third source doctrine in the circumstances: cases in which the third source doctrine had been relied on could be taken as examples of police activity that was lawful because the actions were incidental to ongoing and bona fide police investigations; there was no such investigation underway when Mr Tamiefuna’s photograph was taken. Further, the third source doctrine cannot be relied on and a specific power should be found when a public authority imposes a liability or detriment on a citizen or interferes with a citizen’s liberty or property.
Ultimately, despite it being the fruit of the poison tree of an illegal search, the court decided to allow the evidence to be used (there's a test in the Evidence Act for this), and upheld the conviction. But this came with a pretty significant caveat:
The photographs were, however, admissible as evidence against Mr Tamiefuna. Although the right breached was an important one, the intrusion on it was not very serious. The police’s impropriety was not deliberate, reckless or done in bad faith — though a different conclusion might follow if the police continue to take photographs of persons in circumstances not properly authorised by law.The latter is clear: the police are now on notice that if they continue to violate privacy, evidence and convictions will be thrown out. And since they've known it was illegal since May 2021 (when they admitted it in an internal report), and certainly since the publication of IPCA's report and the issuing of a compliance notice on youth photographs in September 2022, that notice is effectively backdated. The police now need to clean up their act, or the courts will clean it up for them.