I could be wrong, but when we got our new Outback last September, I played around with the battery disconnect switch. With it "off" I could not find anything that had power going to it (shore power was unplugged also). Even the CO2 detector was dead. I then plugged into shore power and the CO2 came back on, as did everything else, and the battery was not charging.
I'm pretty confident, when my switch is "off" and I'm unplugged from shore power, my battery is 100% disconnected. According to my dealer, he says everything is "off", and I can't find any evidence to prove otherwise. I suppose different manufactures do different things there.
I do want to test this further by testing the battery charge when the cables are removed from the posts, vs the shut off over a specified length of time. That's a "Spring" project, once this horrid cold and snow goes away!