I think the main problem with mechanical cameras in the cold is not seizing, but slowing. I had an autocord tnat did that. if you couple that with no availability of a light meter in our "no battery" thought experiment, it becomes hit and miss what you will get. I like an electronic shutter because the springs are always releasing at maximum tension, so the slower speeds stay accurate in the cold. if the battery was really a problem, i could keep a warm spare in my inside pocket, but I have left the Bronica and its silver oxide battery in my car overnight at -12c and no problem shooting in the morning.