It is one of those considerations you know about when you buy your house. If, as a conservative, you decide to move into a leftist enclave, you can expect your neighbors to take offense when you place the campaign sign of a non liberal on your property.
Some of them may even be so incensed by your brazen and rude expression of your First Amendment rights that they decide to correct your politically incorrect error by taking your sign and placing it in the appropriate compost or recycling receptacle.
Typically, when the shoe is on the other foot, and a campaign sign is taken out of a liberal's yard, the lefties will call a press conference, hold a vigil or solidarity march and demand law enforcement action to find out what happened to their $1.50 sign.
Conservatives usually just put up another sign. Shawn Turschak of the People's Republic of Orange County (PROC) tried something different. He wired his McCain/Palin sign to an electric fence. Low current and nonlethal. Just enough to give some corrective feedback to the sign thief. Fortunately for webizens, like you, he also mounted a video camera. Enjoy:
It turns out, one of the thieves was an 8 year old. They do teach'em young in the PROC. Don't draw too many conclusions though, later in the day Turschak caught an elderly woman stealing his signs.