VEHICLE WAS SWITCHED OUT OF PARKED GEAR AND ROLLED WITH CONSUMER'S 3 YEAR OLD SON IN THE DRIVER'S SEAT. TRANSFERRED TO OVSC.*MR THERE WERE NO KEYS IN THE IGNITION. THE VEHICLE ROLLED BACKWARDS ACROSS A STREET AND HIT A TREE. THE CHILD WAS NOT INJURED. THE CONSUMER FEELS THAT THE VEHICLE INTERLOCK SYSTEM FAILED CAUSING THIS ACCIDENT. *NM