>>188666How else are you supposed to know? A property is usually marked by stakes driven into the ground. Good luck finding those innawoods. Maps can be out of date, and property maps rarely show any geographical features. What if you're following a natural formation that's bending this way and that while walking near a property line defined by two stakes half a mile apart?
Maybe in a few years a virtual barrier will pop up in your HUD alerting you to an approaching line but for now we're going to have to deal with posted signs.