You did the right thing.
I know here in Texas it's ilegal to leave dogs in a car, even if the windows are a bit opened. On sunday afternoon I went out with my husband and mom and when we got to the place someone had left a dog in the car. If you live in Texas you can imagine how hot it gets here in the summer.
But someone had called the cops and they were opening the car to get the dog out. And the people were going to be fined for breaking the law.