I PUT OUR TAHOE INTO PARK AND WENT INTO A CONVENIENCE STORE. UNFORTUNATELY, WHEN I CAME BACK MY TAHOE WAS GONE. IT HAD ROLLED DOWN AND OUT OF THE PARKING LOT INTO AN ELECTRIC POLE GUIDE WIRE. BUT, AFTER MUCH RESEARCH, VIDEO REPLAY AND TRYING TO DUPLICATE THE PROBLEM, I THINK I MIGHT UNDERSTAND HAPPENED. YOU CAN ACTUALLY PUT THE GEAR SHIFT LEVER IN A POSITION WHERE IT THINKS ITS IN PARK, WITHOUT THE TRANSMISSION BEING IN PARK. THE INDICATOR SAYS ITS IN PARK, AND THE DOORS UNLOCK, THINKING ITS IN PARK, BUT THE TRANSMISSION ISN'T ACTUALLY LOCKED IN PARK BECAUSE THE LEVER IS IN AN UP POSITION AND NOT BACK. IF YOU HIT THE POWER BUTTON WITH THE LEVER IN THIS UP POSITION, AND GET OUT OF THE VEHICLE WITHOUT LOOKING AT THE DISPLAY SAYING THE "SHIFT TO PARK", THE CAR CAN ROLL BECAUSE ITS ACTUALLY IN REVERSE. FOR ME NO DISPLAY SHOULD SAY ITS IN PARK IF ITS NOT.