The "crime triangle" is a policing theory that identifies the three elements of victimization: a victim present at a location with an offender at the same time and with the offender perceiving an opportunity to commit a crime against the offender without a high risk of being apprehended. CCTV as a surveillance mechanism focuses on the third element, as it introduces a factor at various locations likely to reduce potential offenders' perception that they can commit a crime at that location without being observed and recorded by a video camera. CCTV is generally accepted as a surveillance technology to observe people and their activities in banks, retail outlets, and public places where people congregate for various leisure and business activities. CCTV has not been generally used in residential areas where people typically have a psychological expectation of more privacy than in commercial areas. Although there is no firm pool of statistical evidence that CCTV cameras would definitively reduce crime in areas where they are placed, the Strathclyde Police in Scotland recently claimed a significant decline in crime following the installation of a CCTV system in a community. The expansion of CCTV surveillance is likely to occur as advocates and planners negotiate with those who will be affected at the proposed locations. The central issues for negotiation are whether the proposed location of the cameras has a history of a high crime rate and whether the promise of reducing the crime rate is sufficient to justify the cost in money and loss of privacy.