In February 2012, Police in Christchurch learned that boy racers would be congregating for a cruise. So they waited until they had assembled, closed the road, deployed the riot squad, and detained everyone present in their cars while vehicles and licences were checked. The whole process took seven hours, during which the hundreds of people present were denied food, water and toilet facilities.
Today, the Independent Police Conduct Authority has ruled that this was unlawful detention and that the treatment of those detained violated the Bill of Rights Act:
Police broke the law and breached the human rights of hundreds of people when they blocked off a Christchurch street for seven hours to check about 200 vehicles that had gathered for a charity event, the police watchdog says.
Authority chairman Judge Sir David Carruthers said while they accepted police needed to act to control the situation given their concern about the large number of people gathered and possible disorder, their detention of people, in some cases for more than six hours, and their treatment of them during this time, was unlawful and a breach of human rights.
The full report is here, and its damning of police treatment and their behaviour subsequently. The IPCA initially passed the case to police, but stepped in to investigate themselves after a year due to police foot-dragging. It finds numerous breaches of police policy as well as the law. A key problem? The police in charge - who seem to have been the senior police in the city on that night, though relatively low-ranking - "did not understand the extent, and limitations, of their powers". In particular they didn't understand that detention for traffic stops is explicitly time-limited and simply does not apply to passengers. As a result they detained at hundreds of people unlawfully. And their incompetence could now cost the public hundreds of thousands of dollars in compensation if their victims sue (and they damn well should).
There's no information on whether the officers responsible for this mass violation of human rights have been disciplined. But given the police's past record on such matters, I suspect not.