Those people shouldn´t teach gun safety. Maybe they should not even be allowed to handle a gun. "at all times" can´t be right. It´s not only the cleaning thing. When you need to shoot, it should be loaded and not just treated as if it is. A "Click" instead of a "Bang" is bad enough on a hunting trip.
The "one is none ..." should just be left in the contexts where it actually makes sense.