Rein in Babies and Toddlers

A carer gets off a bus leaving behind a baby in a buggy.
Simple answer to this problem - and the Bulger case.
Attach the mother or carer to the baby or buggy.
Have reins attaching you to the child or the toddler or the buggy. Then the kiddie can't be forgotten, or pulled away. Toddlers cannot run off into traffic or disappear.
Dog leads which extend might be suitable.