Even though Maria Guerrero and her husband childproofed their doors, her mother, Mary Sanchez, sometimes found a way to wander out of the house. A neighbor called one night to report her walking in the middle of the street at 3 a.m. "I said, 'I can't take the chance my mom will wind up walking out on the street and getting hit by a car,'" Guerrero recalled. She looked for a secure nursing home specializing in dementia care and found what she thought was the perfect place: Idle Acre Convalescent, a 59-bed facility behind a wrought-iron fence on a quiet street east of Los Angeles. The facility has Medicare's highest rating, five stars.