For Troy Etherton's dad, Scott, one small incident sums up the way we kill our children's independence and creativity.
When his dad arrived at school to collect him, Troy, 9, was sitting on the grass with a rock.
"He was banging the rock against another rock," Etherton says.
"The teacher came and said, 'Will you stop that!'
"I came up to him afterwards and asked, 'What were you doing with that rock?'
"He said, 'This rock is shaped a little bit like a heart and I was just going to shape it more like a heart so I can show you how much I love you'."
The Ethertons are determined not to let incidents like this stifle their son. They are part of a growing movement to let kids play freely, to learn outdoors and on their own initiative, and to roam.
"For two million years we lived outdoors, so things are a bit weird now for us, and probably that is where a lot of problems come from," says Joey Moncarz, founder of the Deep Green Bush-School near Clevedon.
"Mainstream education is based on the factory model and it doesn't recognise the health and happiness of young people. That's why there is so much bullying in schools."
Moncarz will give a public talk next weekend at an event called ReWild the Child, aimed at reconnecting children with nature.
It is an irony that as the internet has widened children's horizons intellectually, their physical horizons have shrunk.
Tim Gill, a British expert on childhood play who will speak at next week's event, has written the area that children are allowed to roam on their own has shrunk in one generation to one-ninth of what it used to be.
In New Zealand, AUT researchers Julie Bhosale, Scott Duncan and Grant Schofield asked children aged 10-12 and their parents and grandparents how often they were allowed to go by themselves or with friends to local places such as the shops, park, school and other friends' houses.
Averaging all the answers to produce an index, they found free movement dropped slightly between the grandparents' and parents' generations, from 2.54 to 2.28 on the index, but plunged to 1.49 for today's children.
Only 49 per cent of today's children walk, bike or scooter to school, compared with 93 per cent of their parents at the same age.
Only 43 per cent are allowed to bike on main roads unsupervised, compared with 76 per cent of their parents, and only 14 per cent are allowed out after dark unsupervised, compared with 30 per cent of their parents.
Instead, the time of children today is far more organised. On average, today's 10-12-year-olds attend 4.1 organised activities a week, more than twice the average 1.8 activities their parents took part in at the same age.
"It has been the cottonwoolling of children, and more structured activities as opposed to the unstructured licence to roam," Scott Duncan says.
Dangerous traffic has increased exponentially, partly because both parents in most families are now working, leaving less time to walk and play with the children and to get to know the neighbourhood.
"Ten or 20 years ago we did know our neighbours better," says Duncan. "There were more eyes on the street looking out for people because there were less people working."
He says it's time to redefine "good parenting".
"To be a good parent doesn't mean you have to enrol your kid in five or six different things and be ferrying them around everywhere," he says. "Being a good parent could be allowing them licence to explore."
Jan Beatson, founder of Play and Learn kindergartens and another speaker next week, says others have forgotten the value of unstructured play.
"We don't have any toys," she says.
"We do have paper and pens and books and ropes. But a stick can be anything."
Researchers from AUT and Otago Universities have done a study with 16 primary schools in which half made no changes and half relaxed their playground rules, allowing children to climb trees, ride on bikes and scooters, play in the rain and with water, and play with objects many schools would consider rubbish, such as logs and old tyres.
Although objective measures showed little change in physical activity or bullying, the schools believed the changes made their children fitter and better behaved.
At Swanson School, new principal Leandro Piantelli, who came to the school last term after the "free play" policy had been under way for several years, says there have been no serious accidents since he arrived, even though the children can climb trees, play bullrush and play with old wheels, pallets and other leftovers from building sites - because the children learn to be careful.
"I worked in a school where kids were not allowed to climb trees, and we had broken bones virtually every three weeks because they were falling from the children's playground," he says.
"In the past three or four years since they have been running this [at Swanson], accidents have actually reduced, and kids' readiness to learn has increased.
"There is a lot less fighting in the playground, and there are a lot less behaviour incidents in the classroom because the kids have spent 40 minutes to an hour doing what they like. They are tired and they are ready to learn."
But to educators like Beatson and Moncarz, changing school playgrounds is only a first step towards restoring children's independence and creativity. The end goal is to get children out of the classroom and into the wild.
"This is genetically what makes us feel good, being outdoors," Moncarz says.
"A kid doesn't have to be an outdoorsy type, it's just about having the space and freedom and the ability to socialise in a healthy way and not be pressured."
His Deep Green Bush-School is tiny - just 11 pupils aged 5-15. It is believed to be the country's only fulltime school that is entirely outdoors. Students learn practical skills such as gardening and looking after animals, but they also do writing, maths and "debate", with a focus on ecological issues.
Beatson runs two early childhood centres in South Auckland and one in Dunedin, all with a stress on outdoor activity but based in centres because, she says, the New Zealand funding system is based on premises.
She also runs wholly outdoor "nature kindergartens" at Long Bay Regional Park, Camp Sladdin at Clevedon and Schlaepfer Park at Paerata.
Auckland mothers Rita Pontes and Maria Mariotti run nature-based holiday and after-school programmes and one-day open-air programmes for primary school-aged children at Long Bay and Blockhouse Bay through their company, Conscious Kids.
Troy Etherton is one of about 60 children aged 5-14 who attend another one-day programme at The Forest School in a 4ha bush block at Hatfields Beach just north of Orewa. The school runs three days a week, with about 20 children each day.
When the Herald on Sunday visited this week, Troy was in a group building a raft using wood the children had cut from a stand of bamboo.
Another group was building "sculptures" out of bamboo and various "waste" materials. A third group was learning to safely use sharp knives to whittle wood.
Kaden Carr, 8, showed us "secret hiding places" in the bush, a "vampire base" that is the centre of fantasy games, tree huts, a bird's nest and a "bug hotel" - a wood and pipe contraption for housing creatures found in the bush by the children that includes water for the bugs to drink.
A psychologist works one-on-one with Tom, who is autistic and largely non-verbal but unusually intelligent. Tom attends a regular school for the other four days of the week and Forest School director Tennille Murdoch says the other school is "rapt at how this is allowing him to integrate back into the school".
"By default we are getting a lot of children that have really high levels of anxieties and other learning differences and needs," she says.
"Some of the symptoms you would see in a classroom we don't see, because their bodies are being fed what they need physically and emotionally. They are able to be successful."
Lisa Bodley, whose son Ari, 8, and daughter Freya, 5, attend the school, says Ari is "brilliant" at anything mechanical, but is not academic.
"He was becoming quieter and quieter at school. He sort of withdrew, he started washing his hands excessively and just really struggling," she says.
At the Forest School he has built a boat, is building a tree hut and has become a leader in various activities.
"He has this new sense of confidence," his mum says. "He is happy and basically full of life again."
Jennifer Salmon's daughter, at 14, is the oldest child at the school. Her mum describes her as very intelligent but dyslexic, and much better with her hands than with words. At the Forest School, Murdoch and her husband, Gavin Murdoch, helped her build a flying fox.
"What she needed was to take ownership of it, and they just set her free," says Salmon.
Scott Etherton says Troy has mild Asperger's Syndrome and struggles with social interaction at his regular school, but at the Forest School he has learned new social skills.
"Autism is a physical condition, but I think that if you were to ask, is cooping kids up in a classroom for five hours exacerbating the symptoms, I'd say, definitely," he says.
At the Forest School, Troy was recently awarded the "manaaki stone", which is given at the end of each day to the person who has made the best contribution.
"Troy got it because he organised a game and specifically sought out a new kid who was not fitting in and said, 'Why don't you come and play this game, because I know what it's like to be left out'," his dad says.
"I would just like to see the Forest School type of thing rolled into normal schools so all kids get to spend time outside."
• ReWild the Child, The Parenting Place, 300 Great South Rd, Greenlane, Auckland, Sat Nov 25, 2pm-4.30pm, $29.
Peter Lewis is upgrading his 12 rentals but has questioned why others are exempt.