You know….when I read this…my first reaction was…you have GOT to be kidding me. Watched the video, and thought…dear god thats stupid.
It works.

To spare you the video: take a car with locked doors. Take tennis ball with small hole in it. Place tennis ball on the keyhold, with hole lined up with the keyhole. Press the ball as hard as you can, forcing air into the hole. Watch in amazment and disgust as your car now magically opens. Watch the video on Crooked Brains