It is not enough for a person simply to be able to defend his environment, he must also want to defend it. The term ownership when used in this context does not necessarily mean actual legal ownership. It can be, and very often is, a perceived ownership resulting from an individual's relationship with the environment. Office workers, for instance, may feel a sense of ownership for the office in which they work. Surveillance Surveillance is the principal weapon in the protection of a defensible space.
Criminals are least likely to act when there is a high risk of their actions being witnessed.
Environments in which legitimate occupants can exercise a high degree of visual control increase the likelihood of criminal acts being observed and reported. Opportunities for informal or natural surveillance occur as a direct result of architectural design. Designs that minimize visual obstacles and eliminate places of concealment for potential assailants offer the most protection against crime. These open designs also encourage use of the environment, as people feel safer when they can easily see and be seen. The use of defensible space in conjunction with natural surveillance is a potent crime prevention tool.