TOW RECEIVER HITCH DISCONNECTED FROM VEHICLE WHILE TOWING SMALL BOAT TRAILER. FORTUNATELY NO ONE WAS INJURED BUT ACCIDENT COULD HAVE CAUSED SERIOUS INJURIES IF TRAILER OVERTURNED ON INTERSTATE. ACCIDENT CAUSED BY A DESIGN DEFECT IN THE PIN ASSEMBLY THAT HOLDS HITCH TO VEHICLE. THE PIN RETAINER CAN BECOME DISLODGED AS VEHICLE VIBRATION CAUSES IT TO RIDE UP OVER BRACKETS THAT HOLD HITCH TO VEHICLE. THIS VEHICLE WAS PURCHASED AS A TOW VEHICLE BUT IT CLEARLY CAN NOT BE USED AS SUCH DUE TO THIS MANUFACTURER DESIGN DEFECT. SINCE MOST TOYOTA HIGHLANDERS ARE SOLD IN THE NEW ENGLAND AREA WITH THE FACTORY TOW PACKAGE. THIS DEFECT COULD LEAD TO OTHER SERIOUS ACCIDENTS. DT