It is all fine and well not leaving dogs in cars but what people also need to be aware of is that you can have your dog stollen from outside of the car too. Leaving them tied outside shops, on walks and even in your own house or garden! I am sure I put up several months ago about a woman who had one of her golden retrievers stollen from her own garden. She must have been targeted as a breeder or at very least watched for some time to make sure of the perfect time to snatch the dog. She was in the house when it happened and had only looked away from the window for a second.
I know you cannot keep your eyes on your dogs at all times, but be aware of your surroundings and anything different or any odd characters in your area. For show dog owners it might be an idea to withold your addresses from the programmes. I know I have not done this in the past but I am going to take care to when entering in the future.