Recently, there has been a spate of armed bank robberies in my neighborhood, and customers have been held up at gunpoint in the local deli. This is a serious situation, and it has gotten a serious reaction from both the community and the police. One of the moves that the police have made is to have an empty police car parked on the main street near the banks. The theory is that if a potential bandit happens to be driving through the area and spots the patrol car, he'll keep driving rather than stop and rob.
What concerns me is that the police department has explained all this in the local newspaper. Yep, they've actually told the public that the police car is always empty and gets moved a few times a day, and it's just a decoy. So now, every potential robber who reads that paper will know he has nothing to fear from the non-existent police in that empty car. That's like taking an ad out in the paper saying, "We'll be out of town for a week. Our lights and TV will remain on, but that's just to try to fool people into thinking we're home."
But out of respect for the police, I'm willing to support this tactic and see how it works out. I do think there are a few things they could do to make the whole thing more convincing. They could record some voices that would randomly come from the empty car. So, if a crook passes by, he'd hear things like,
COP #1: "So, is the Captain still mad at you for beating up that guy?"
COP #2: "A little. But he understands the pressure we're under makes us a little crazed."
COP #1: "I don't know which tastes worse — these donuts or the coffee."