I actually think that the dogs would have been fine for a short period of time, unlike in hot weather, and yes, I have waited in the car in cold weather as a kid, and survived fine. Especially with multiple dogs, and not knowing how long they were going to be inside, I wouldn't have been too worried. If they had luggage and were at a train or bus station, yes, but ... I actually don't think we know enough to call them irresponsible at this point.