I live in Wisconsin, and every time the weather gets cold people tell me to make sure I keep my gas tank full. When I ask them why they don't have an answer. Why do people always tell me to keep my tank full in the winter? Does it have something to do with condensation forming in the tank? Is it just so there's more weight in the back in case it snows? I've been wondering about this for years. Can someone explain this to me? Thanks.