This is indeed a great idea. It might also help people to think twice before leaving their dog in a car, if they see a group doing this.
I often do a patrol myself, in warm or hot weather, in the car park when I go to the supermarket. So far I have only once had to rush into the store, with the car make & registration and ask for a message to be put out over the tannoy. In that instance, the woman was very annoyed with me, saying "I have only been five minutes!" I didn't say much but to mention how dangerous it was even for a few minutes.
I often do a patrol myself, in warm or hot weather, in the car park when I go to the supermarket. So far I have only once had to rush into the store, with the car make & registration and ask for a message to be put out over the tannoy. In that instance, the woman was very annoyed with me, saying "I have only been five minutes!" I didn't say much but to mention how dangerous it was even for a few minutes.