I live opposite a primary school. There's a mum who collects her nursery child at 11.30 then sits in the car with her until the older children finish at 3pm. She usually sits there with the engine running which is right next to the playground. I'm not sure if I should do anything or if I'm being a busy body.
I know the little one is in there because I did ask the mum to turn off her engine during the really hot weather. I got an earful because apparently she needed it on because it was hot in the car.
Yabu- keep your nose out
Yanbu- you should notify the school/authorities