We can always tell when someone is using gps to get to our house because they stop a hundred yards short and are looking on the wrong side of the street. Especially fun when it's the pizza guy-when i order online, I give pretty specific directions that they then ignore as if gps knows where I live better than i do.
Our house is off by more than a mile. So I have to give landmarks. If you use GPS, you're going to end up at someone's house, but not mine.