Phone addiction is reshaping school students' brains - but Meningie's school is leading the way in finding an answer.
Last Wednesday, Meningie Area School began a trial in which students are asked to put their phones on airplane mode and lock them in a special pouch when they arrive each day.
Like the tags used on clothing or DVDs in shops, the pouches can only be unlocked using a special device.
The results, said wellbeing coordinator Emma Oliver, had been dramatic and immediate.
"Day one was amazing," she said.
"I was walking through the senior school and they were around a table, their heads were up, they were talking, laughing, having conversations.
"Normally it's silent.
"In the middle school they were excited because they've got their friends back.
"I think it's going to be a really positive thing and is really going to take off - it's simple and it works."
Ms Oliver was inspired to contact the company which makes the pouch system, Yondr, after being asked to use it at a show by comedian Hannah Gadsby earlier this year.
The trend began on Broadway in New York City relatively recently.
"Every school I've been at struggles with how to manage the mobile phone thing," she said.
"You can ban them, but they're so addictive it becomes confrontational and you end up doing a lot of behaviour management, detentions and phone calls home."
Most teenagers knew their smartphone use was unhealthy, as it affected sleeping habits and anxiety levels, Ms Oliver said.
Some experienced genuine separation anxiety when their phones were taken away, or worried that someone would uncover their private communications and searches.
But few knew how to control the problem, and almost all at the school had been happy to give the Yondr trial a go.
Its appeal was that students still had their phones with them, and could even decorate or personalise their cases, which they would keep until they graduated.
The trial, a first in SA, cost the school only a few hundred dollars.
Yondr implementation manager Elle Duggan-Crouch said the company's longest-running Australian trial had produced encouraging results.
She said Wauchope High School in New South Wales, which has been participating since June, had reported a 60 per cent drop in detentions and increased student engagement with their lessons.
Supporters argue that phones are a distraction and expose students to cyberbullying.