In most cities, residents might warn off would-be criminals with a window decal from their home security provider, or maybe a “Beware of Dog” yard sign when the pooch in question is nothing but a cuddly lapdog.

The crime deterrent of choice for Palm Beach’s ultra-high-powered neighborhoods? A spare police car parked at the end of the driveway, naturally.

If you’re an eagled-eyed Palm Beach resident, you almost certainly have noticed police cars regularly parked at the most coveted estates on Billionaires Row. But these multimillion-dollar homes aren’t necessarily on the scheduled Palm Beach Police patrol routes—instead, vigilant citizens looking to add a little extra boost to their home security plans are renting out unused police vehicles. After all, don’t extraordinary homes deserve over-the-top protection measures?

And the Palm Beach Police are seeing benefits on their end, too: These days, many police cars are sitting dormant while able-bodied officers bike to patrol their beats on Palm Beach. That means the Palm Beach Police & Fire Foundation can provide cars—with or without an officer—to help guard property at a fee ranging from $50 to $150 per hour.

“It simply depends on how much you want to spend to get either an unoccupied car, a car with an officer, a uniformed officer or an armed guard,” said one local resident. “Most are retired cops.”

Sounds like a win for all parties: The Palm Beach Police force gets to put extra cars to use for fundraising purposes, while residents can sleep a little sounder at night knowing one is parked at the end of their driveway.