"Innocent" Kiwis who were exposed to live video of the Christchurch shootings should not be too concerned about getting into trouble with authorities for watching it, the country's chief censor says.
Anecdotal evidence suggests the video was widely viewed by young people on the day of the shooting.
"While we do not have the numbers yet, it is clear that this video was 'pushed' to many innocent New Zealanders by various apps. We have had reports that it also 'auto-played' for some people who did not even know what it was," chief censor David Shanks said.
The video has been classed as an "objectionable" publication, meaning watching it could carry a 10 year jail term, but common sense appears certain to apply, Shanks suggested.
"Enforcement around objectionable material is a primary responsibility of Internal Affairs and I have discussed with them the need for a balanced approach to enforcement in this case," he said.
"I don't think New Zealanders innocently caught up in the social media storm following these horrific events need to be concerned.
"The enforcement focus will likely be on those actively and maliciously involved in spreading this material, and taking actions such as deliberately distorting it to avoid blocks and detection software."
That said, the time for any excuses for seeking out the video was over, he indicated.
"Every New Zealander should now be clear that this clip is an illegal, harmful and reprehensible record created to promote a terrorist cause. If you have a record of it, you must delete it.
"If you see it, you should report it. Possessing or distributing it is illegal, and only supports a criminal agenda," Shanks said.
Few Kiwis would have given much to the Objectionable Publications Act being used a tool against terrorism, prior to the widespread circulation of the horrific video live-streaming the Christchurch mosque shootings.
The law can be used to punish people who create, distribute or simply look at material that "deals with matters such as sex, horror, crime, cruelty or violence in such a manner that the availability of the publication is likely to be injurious to the public good".
But the potential penalties are severe, with a maximum 10-year jail term for viewing objectionable material and a maximum 14-year term for "distributing" or republishing it.
"Republishing" could include something as simple as retweeting an objectionable publication or sharing it on Facebook.
Nor does a video or other publication first need to be classified by any authority as "objectionable" in order for there to be an offence.
Ignorance of the law – for example, ignorance in this case that a video of the Christchurch shooting is objectionable – is not an excuse.
On Monday, Shanks officially classified "the full 17 minute video" of the Christchurch shootings as objectionable, because of its depiction and promotion of extreme violence and terrorism.
But that wasn't required for viewing the video to become an offence.
Shanks' initial statement caused some confusion.
Spark and Facebook appeared to interpret it as meaning that watching or sharing any part of the video would be offence, while Google assumed it meant only the original video in its entirety had been classified as "objectionable".
On that basis, Google-owned YouTube has been continuing to host overseas news reports that contain some clips from the video, showing the attacker preparing for, but not carrying out, the atrocity.
Shanks has now provided further clarification.
"The classification of the complete video did not automatically mean that any image or short extract from it was also objectionable," he said.
"However it is very important for people to be aware that any edited clips, screenshots or still images taken from the full video, that depict scenes of violence, injury or death, or that promote terrorism, may well also be objectionable," he said.
There are several ways police could know that someone has watched or shared the video.
Legitimate websites that have accidently hosted the material could be forced to turn information over to police. People could be identified by their "internet protocol" addresses with the help of their internet provider.
Shady foreign websites that have hosted the video to promote the terrorist act might not be willing to provide such cooperation to authorities.
But they could be raided and have that information exposed, either now or down the track.
Anyone who accesses the video over peer-to-peer file sharing sites could be outed if the video is then uploaded from their computer.
Internal Affairs has a division that attempts to identify people who are sharing objectionable content, including by working "undercover" in online chatrooms.