Apparently, inner-city farming is a hot career. In Brooklyn, Pittsburgh, and downtown Louisville, Ky., more Hondas, Lexuses, and Mini Coopers are engaging in good, old-fashioned field labor.

Sound odd? Actually, it's shrewd. And dishonest. Drivers get a sweet break on their premiums if their vehicles are used exclusively on a farm. With rising insurance costs, more people are claiming their cars are engaged in this pursuit of agricultural excellence. The price break for rural vehicles makes sense. Until pigs develop opposable thumbs, there seems little chance of collisions, much less thefts or a window smashing to get at that Hermes bag filled with new scarves.

Rating errors, including misapplied farming discounts, cost the auto insurance industry more than $13 billion in lost revenue annually, according to San Francisco-based Quality Planning Corp. That hefty tab is passed on to upstanding urban- and suburbanites.

If you're looking for an honest price break on your car insurance, consider the following:

  • Buy from the same company that handles your homeowner's or renter's insurance.
  • Take a defensive driving course.
  • Use an approved (by your insurer) antitheft device.
  • House your car in a garage versus on the street.
  • Mention membership in some professional association and see if it provides bulk business to the insurer.
  • If a teen is on your policy, encourage her to keep up her grades.

For more ideas, check out our The Fool Insurance Center.