FRONT PASSENGER SIDE HEADREST SPONTANEOUSLY POPPED OPEN WHILE STOPPED AT A RED LIGHT. NO ONE WAS IN THE PASSENGER SEAT, NOTHING HIT THE SEAT OR HEADREST, NO SUDDEN HARD BREAKING OCCURRED AND NOTHING HIT THE CAR. NOR WAS THERE ANY FORM OF ACCIDENT BEFORE OR DURING THIS INCIDENT. ABOUT 6 MONTHS LATER, THE DRIVER'S SEAT HEADREST SPONTANEOUSLY POPPED OPEN WHILE MY HUSBAND WAS SITTING IN THE SEAT. THE CAR WAS IN PARK AND WAS NOT RUNNING. SAME AS WITH THE PASSENGER SIDE, NOTHING HIT IT, THE SEAT OR CAR. NOR HAD THERE BEEN AN ACCIDENT AT ANY POINT.