I didn't closely read every last post and reply in this thread, but it seems to me that some are jumping to conclusions with Cagneydog's situation. I'm sure she would never leave her boy in a hot car while she went in somewhere. I also agree with Par about it depending on the situation. I say this because I was one of those "evil" people who used to take Cody everywhere with me and he'd stay in the car when I ran into the store for something etc. This was only in the fall and winter, and never in the summer. The doors were locked and windows up with a crack left open for a bit of fresh air even if it was quite cold out (cold didn't bother him, he had quite a coat). He absolutely loved going with me whether he got to come out of the car with me or not. I would leave him for up to 20 minutes or so (of course I never took him if it was to be a LONG absence), and he'd doze off and sleep or watch people walking to and from their cars.

I didn't take Willie because he didn't enjoy it. I don't take the T's unless they are coming out with me because I know they'd be anxious to get left. But Cody was a different dog, different personality, and I knew him enough to know he really loved going even if he got left for short periods of time.