I'm assuming he's referring to children on their way home from school, and not people who are at that school, gone home and got changed.
It's quite common, I think. They want them to walk home from school in proper uniform.
Rightly or wrongly - people complain
My eldest son's 'uniform' is a polo shirt with the schools logo on, a sweatshirt with the school's logo on, jeans and trainers.
It's a great school, fab kids, brilliant results - but the local people are forever moaning about how the children look as they walk home from school. So much so that the school is considering a uniform change.
See, to me, what matters is that it's a great school, the children are lovely, the school gets fab results, the staff are well motivated...
But no, what matters to the local shopkeeper and the person looking out of their window at 3:30pm is that there are lots of kids walking down the street in jeans.