Electronic rust control module. Science or Scam?

My wife and I recently purchased our first brand new car. At the dealership, they asked us if we wanted an electronic rust control module installed on our new car for the hefty price of $450. We said "no thanks", but I have been thinking lately.... Do these things really work?

What do you all think.... Are these things a gimmick, or do they really offer serious rust protection for your car?