According to this recent Reuters video, South Korean prisons are testing robotic prison guards to patrol corridors and monitor the behavior of inmates. The robot, equipped with several cameras and microphones, moves around autonomously and thanks to the cameras and advanced human behavior recognition it can inform human guards about abnormal prisoner activity. The two-way communication system allows the guards to talk and listen to the inmates without going there, just using a tablet computer. The robot is unable to act on behalf of the real guards, so when anything has to be done, humans must be called to the scene.
RobotBG note: The real invention of the system seems to be the intelligent human behavior recognition and prediction system that is able to analyze the activity of the prisoners and detect if that is different from what is expected. The robotic form adds so little, that the same functionality could have been built into a suspended camera head attached to a ceiling rail system.