Based on the current advertising campaign from the New Zealand Police it would seem graffiti is okay as long as they do it.
There are a series of images of police at work, interacting with people. I’ve seen the images used on bus shelters and even painted directly onto external walls of buildings.
There’s no mistake, the image is a stencilled image. It isn’t a photo. Would this not be graffiti? 
I couldn’t help but think how much the image reminded me of another more famous image. As much as Bansky is admired he is also hated by local authorities who often can’t wait to paint over the images. They consider it graffiti, vandalism, defacing the neighbourhood. The fact that many pay huge sums of money for a Bansky original doesn’t seem to matter.
The origins of the NZ police image above are noble. The work was part of a series created by artist Otis Frizzell for a police recruitment initiative, which aimed to acknowledge the work undertaken by emergency responders in the aftermath of the earthquake in Christchurch in February. In a great sense of irony a copy of the artwork was unveiled in Christchurch and then later vandalised, graffitied over. You can read about the other images and the stories behind them.
Really, I have no problem with the campaign. I like stencil art and frequently photograph it. I notice there is some painted on the walls of a building near the left bank off Cuba Mall in Wellington. The problem with this is that in the name of the fucking rugby world cup and all the extra tourists who will be flocking to Cuba Mall, the whole area has been cleaned up by the over zealous council. They are concerned that visitors here for that stupid game don’t feel threatened in our city. In the process they are destroying the flavour of the place. And yet it is okay to paint up a similar image as long as it is a Police advertisement.