SAN FRANCISCO — From her apartment at the foot of the celebrated zigzags of Lombard Street, Judith Calson has twice peered out her window as thieves smashed their way into cars and snatched whatever they could. She has seen foreign tourists cry after cash and passports were stolen. She shudders when she recounts the story of the Thai tourist who was shot because he resisted thieves taking his camera. And that is her tally from the last year alone. “I never thought of this area as a high-crime neighborhood,” Ms. Calson, a retired photographer, said of this leafy part of...