Next time, you need to intervene. The leaving of the children in the store put them in your care, to all intents and purposes. My partner and I called the police after 10 minutes when a couple kids the same age were left outside Tinseltown Mall. It was a painful process, but nevertheless, it made the abandonment and the acknowledging of responsibility clear. It was the same situation, more or less, and possibly the same people - the police (the social services car) would then know the ostensible care-givers. Point is, not to wait and get all exhausted mentally - just intervene.