I am a LAME Rated on the B737NG and what was said on the news was said by the lady on the news was incorrect about the B737-800 aircraft light in the tail end, thats why the plane moved. I totally disagree with that woman. I
The only way the plane would of move is the "PARK BRAKE" was "OFF", a common practise to do once the aircraft is chocked to stop the disks sticking together and aid cooling. But on a windy day normally you would leave the "PARK BRAKE SET to ON" as well as the plane chocked. Also the tow bar was attached to the plane, and the Nose Wheel Steering Bypass pin installed there is No Hydraulic Power to the Nose wheel steering so you can freely move the Nose Wheels easily from the tow bar attached. So with all these factors brakes released, no wonder the plane moved.
I think the Pilot would have had half a clue to leave the brakes parked on a windy, and the gnd handlers to chock all wheels. I guess thats wat happens when u are on a tight schedule. People slip up and there are no engineers are there to help as the Airline chooses not to have them there participating in th turnaround. " Low cost Carriers"