Did that change after the case (quite some years ago) a girl was abducted on her way home and the abductor wanted to ransom her but the underground room he built to hold her hostage was poorly ventilated and she died of CO poisoning and at least for a time some people became somewhat more concerned about their kids roaming freely?

Sometimes freak events have an oversized effect on people. In the US people used to park their baby strollers outside stores while they went shopping. One day, I think in the mid 50s, on Long Island, I believe, a family’s sleeping toddler in a stroller/pram was abducted and scared everyone from leaving their kids unattended in a stroller.