I don't know that inappropriate use of personal electronic devices can be considered an addiction as characterized by the initial poster since that suggests an a disease or involuntary compulsion, etc. It might also suggest that the employer has a responsibility to intervene and "help" employees who they find are suffering from such a condition.

This latter point leads us to a major purpose for installing surveillance devices in the first place. Regardless of the actions of the bus driver, once could certainly argue that such equipment can serve as a deterrent – especially when knowledge about them becomes more widespread. (We can pause here and thank Holley for his/her public spiritedness.) But there are other reasons why cameras are now being installed in some locomotive cabs, in automated teller machines, at traffic intersections, etc. It is also why event recorders are required in commercial aircraft and locomotives and why automakers have been installing recording accelerometers in automobiles with air bags and why tachographs have been found in commercial vehicles for decades. It is for post-accident investigation and to protect from liability.

One can question why Metrolink chose to move in that direction - and perhaps for moving ahead with the interim installation of ATS when the more comprehensive Positive Train Control has been mandated for deployment by 2015. One might also wonder about choosing Crash Energy Management features in their new order of railcars when doubts remain about whether this design might have unintended consequences. Part of the answer is our tort-based legal system where management is liable if they cannot demonstrate they have done everything possible when faced with ruinous lawsuits. To muster a successful defense Metrolink probably will not have to hire drones to monitor every camera as a systematic sampling could establish a vigilant effort.