We have a lot of desert around here. Sometimes it's hard to tell road from trail and signs are limited let alone gates. The 1 sign that works the best is "Military Base- Government property- DO NOT ENTER ". If you happen to miss the sign you will either be greeted by an Apache helicopter or a few HV's with heavily armed soldiers. Neither of which is a pleasant experience. Another one that works pretty well is " Federal Detention area ahead ". I think Glen's best choice (without the open gate method) is the "Private Road no Outlet." They have to see it before they turn in or they are already committed to being stupid. :<0)