From the article: "North Ayrshire Council said 97 per cent of children or their parents had consented to the new system"

With a wording like that and a percentage that high, I imagine it went down more or less like that: an adult explain to the kids in 5min what this does and how it will be better for everyone. Then ask kids to raise their hands if they are against it. And voila: 97% of the kids agree.