There is a pediatric neurologist in Far Rockaway who is the doctor all Rabbonim from all over the world consult with in any emergency with neurological problems,even if it is Shabbos. His wife works with my sister and she tells of how her husband knocks on peoples doors,(especially on Shabbos afternoon when many kids are on their own and do whatever they shouldn’t be doing )and gives the parents the type of mussar you gave and how they just leave their kids hefker. If they talk back to him he tells them that now they are yelling at him and when there is a problem they come running and begging to him for help even if on Shabbos or Yom Tov.
There is a hospital in Manhattan, if i remember correctly it is Cabrini which has one floor of children who are brain damaged and living as vegetables lo aleinu some as result of such as not wearing a helmet while riding a bike.
If our grandchildren are caught without their helmets, the bikes are taken away. It’s the law of the land and Dina D’Malchusa Dina!
Your were 100% right.