Thank goodness it is against the law in Arizona to ever leave a dog in a parked car, even in the winter time when the temps might be in the 70's or 80's. A car can heat up so fast even in these temperatures. The police are wonderful and will come immediately and break the car window. Many a surprised visitor from out of state has come back out from their "shopping" to find a police officer waiting for them with a ticket and a broken window.
I applaud anyone that reacts to these situations, because frankly I think the life of the dog is more important than someone not done with their shopping. This holds true also for leaving children in the cars.
Many a time I have told people that have just gotten out of their car and are walking away with the dog locked in the car that it is illegal and some have told me to mind my own blanking business and kept going (aren't cell phones great for calling the police) and others have appreciated the information and went back to their cars.