Critics have argued that electronic monitoring is a more severe punishment than imprisonment because of the "invisible boundaries" and the psychological strain they impose. Proponents say that the invisible walls foster personal accountability and responsibility. Electronic monitoring has three principal advantages: it is relatively cheap, acceptably punitive, and sufficiently controlling to command the confidence of the courts. However, in the operation of programs, two other issues have also arisen concerning the reliability of the technology and its appropriateness to stressful social conditions. It is important for the Probation Service to clarify the ethical, practical, and operational questions regarding electronic monitoring and to consider the place and function it has within the criminal justice system in England and Wales. Bibliography.