It's not something to think about. It's an easy call. If I saw a child or pet left in a car on a hot day, I'd call the police. Why is this even a discussion, as if there is a grey area or something?
I lived for a long time in the desert and would see dogs in distress in a car occasionally. Out there folks would just break a window immediately. None of the arm waving and gnashing of teeth just boom a window was gone.