YUMA, AZ—The steady, back-and-forth motions of a 1979 Ford Econoline van sent "a clear message" to local resident Paul Dunne Monday, discouraging him from knocking. "I needed a jump-start for my car, and the closest vehicle was this van," Dunne said. "I was about to knock on the back window, but when I noticed that the van was clearly rocking, I didn't bother." Dunne instead received assistance from an adjacent, non-rocking vehicle.