If its not tied down people will take it. Recently the local kids in my neighborhood had been working on the stop sign right next to my house and it finally fell over, though still attached at the ground.
Last Sunday evening my dogs start going nuts, by the time I get up I see a jeep driving away with the pole of the stop sign sticking out of the passenger window.
I went to work a few hours later and he traded the stop sign for 2 40 ounce Coors Cans, he left them on the sidewalk next to it. I guess he worked on it for a while before just bending it and dropping it, the noise that my dogs heard, but I guess it did the trick because it snapped off at the base.
I called the cops but since I couldn't get a plate because it was too dark, they could care less. Its on some list to be replaced, probably next year sometime.