"2. Cars and vans (etc): If you want to leave the van a/c or heat on, the motor must be running, which means the key is in the ignition and the gearshift is in Park. And if the key is in the ignition and running, isn't it impossible to lock the door? "
We have been known to leave our vehicle running as long as 4 hrs, while riding a Tour Train here in WV.
Our dog wasn't allowed on the train, so we left her in the car, went on the ride and then came back, it was 4 hrs long and the dog was OK and no one got all bent because we left her in the vehicle while it was hot.
We do it all the time, when going shopping, whatever, she goes were we go, so if we need to leave her in the vehicle, we leave it running.
Our vehicles allow us to leave it on, and lock the doors too. Some won't allow you to do this, but we have fooled the vehicle by locking the vehicle from the passenger side, after the driver gets out.
Gotta' keep those pets cool, when it is warm, and warm when it is cool.
Sharon