On reflection, I still find Wilmslow High School's inclusion in the list surprising, nothing to do with the honesty of children in my locality, but because I thought there was always a ticket check on arrival in the mornings at Wilmslow station. This certainly used to be my experience, because I noticed it when I used the station in the mornings. Maybe Northern did away with this? Wilmslow doesn't have barriers, and later in the day it very rarely has a person checking tickets of arriving passengers, but the Northern staff were always present in the mornings to check tickets and to sell tickets to departing passengers to reduce the queues for the ticket office and the (incomprehensible, in the main) ticket machines.
Maybe people only bought singles for the morning journey and didn't bother for their return journeys, that may have saved some pennies? However this probably doesn't make sense if two singles are more expensive than a peak day return, which I'm sure they are .....