How dumb can you be? A reader told CAR TALK columnists Click & Clack that she had parked her car on a slope in Golden Gate Park and did not curb the wheels, set the parking brake, or leave the stick shift in first gear. When she returned to her car, she found a note on the windshield and a piece of wood blocking one of her front tires. Apparently her car had rolled forward and some Good Samaritan had saved the day. She told Click & Clack that she couldn't believe someone would go to all that trouble. Click & Clack advised always taking all three precautions in case one or more of them fails: When parking on a hill, curb your wheels, set the parking brake, and if you have a standard transmission, leave the car in first gear.