He was satisfied the camp wasn't to blame because its staff were unaware of Everson's past.
Justice Lang said Everson had been living at the camp before he was employed as a groundsman and didn't have anything to do with the visitors.
At the end of 2010 he became aware children would be going there for school camps. In April 2011 he became involved in helping with dirtkart rides because the previous person had resigned.
Justice Lang said alarm bells should've sounded for Everson when he realised there would be children at the camp and he should never have allowed himself to become involved with the children's activities.
On April 11 and 13 Everson helped some of the girls put on their seatbelts and on occasions took them for a ride on the two-seated karts. Everson touched the girls' breasts on top of and under their clothes, Judge Lang said.
Justice Lang told Everson the consequences of his offending went well beyond the girls and included the school's teachers and the venue of the camp.
Parents became reluctant to send their children to school camps when this type of offending occurred, Justice Lang said.
The principal of the Eastern Bay of Plenty school cried while confronting Everson in court.
"Mathew Everson has tainted our class for 2011. Whenever we are reminded of camp there is an uneasy silence and a shifting of bodies that shows how he has harmed us all. They [the victims] felt uncomfortable, frightened, dirty and scared that you would come back to the camp later and do worse... you have harmed us in a way they will never forget," the principal told Everson yesterday.
While reading out the victim impact statement the principal apologised.
"I am sorry that I took those kids to camp. I am sorry that I had to stand in front of the parents and tell them what had gone on and happened on my watch with their kids and that they hadn't been protected the way I had promised they would be."
The principal said one of the victims was sexually assaulted on her birthday and her future birthdays would be tainted.
The principal said Everson's offending had damaged the camp owner's reputation and credibility.
The principal said while the camp had made a mistake in not following procedures to keep children safe, Everson should've stayed away.
"I blame you Matthew Everson and no one else for what our girls have been through."
More than 20 people including some of the victims were in court yesterday. One of the victims broke down while reading her statement in court. She said Everson had taken away her self confidence, she had suffered unbearable nightmares and had trouble being alone.
Everson's lawyer, Roger Gowing, asked that Everson be given a finite jail term and be the subject of extended supervision on his release from jail.
Justice Lang said preventive detention was the only way of protecting the community from Everson.
The camp didn't want to comment when contacted yesterday.