Just found a very slight acquaintance's 2 kids (5 and 3!) playing in the street with their front door open. Said their dad had just gone out to the car and they'd been waiting for him to get back. They trotted off to the car park to look for him (leaving the front door wide open) but he was nowhere in sight. My 2 year old started playing with them on the pavement and I asked the 5 year old whether he had any older brothers, sisters, mum etc at home - no, mum was away and he was the oldest. After about 25 minutes I thought I'd leave a note on the door for the dad and take them to our house just up the street for tea (it was 6pm). They got me a paper and pen and I left a short note saying "Kids are at [address] - they weren't sure where you were - found them in the street!" As I was leaving the note on the door the dad got back, pretty pissed off to see me there, tore the note off the door and said "he knows he's not supposed to go out of the front door". House, by the way, was a tip. He had told them he was going out to the car and had gone to the shops instead.
I'm inclined not to do anything about it but it makes me uncomfortable... Any thoughts?