Oh! That triggered a memory of another unsupervised child. On another continent. We were driving back home from small town Saturday morning shopping on a main (four lane but not massively busy) road and a child crossed all four lanes in front of us. Told DH to stop and got out, leaving my three with him.
Caught up with child who was trotting purposefully across grassed area towards sand dunes and beach. No relevant adult in sight; no adult at all. Child was barefoot and in a nappy and t-shirt, age at a guess 18-24 months. Not coherently verbal but clutching a coin in his palm and wanting ice cream. I think he was on a shopping trip! No ice cream kiosk in the vicinity.
Scooped him up and set off to hawk him up and down the houses, nice older ones, lining the far side of the road. Man in a garden disclaimed child but said there was a party going on a few doors down. Found party house with gate open, knocked on door, which was ajar, nobody came. Pushed door open, heard partyish noises of music and adult chatter from further in, called out, nobody came. Proceeded down a passage, through a kitchen and out into a nice backyard where a lunchtime barbecue was going on: a dozen or so adults, various children, food, beer, laughter etc.
Asked if anyone was missing a child and handed him over to nice young woman who claimed him. She hadn't missed him and was totally unfazed when told how far he had got. Stressed that gate and front door had been open. She offered me casual thanks and I left, shutting front door and gate carefully.
Went home, hugged my kids and shook for ten minutes or so at the thought of what could have happened!