Last time Barbara Boxer ran for Senate, there was only one Boxer sign in my whole town in conservative Orange County. It was a bad xerox, and stapled to a phone pole on a public sidewalk.
I was driving by and pulled over and took it down. My son was horrified. "You stole that!". "No, I'm taking out the trash. Yhe Boxer campaign doesn't own the phone pole."
In some states you can be fined for attaching a sign to a telephone pole.