Page 926 - (ISC)² CISSP Certified Information Systems Security Professional Official Study Guide

determines the reach of a security policy in the physical realm. This
can be the walls of an office, the walls of a building, or the fence

around a campus. In secured environments, warning signs are posted
indicating that unauthorized access is prohibited and attempts to gain
access will be thwarted and result in prosecution.

When transforming a security policy into actual controls, you must
consider each environment and security boundary separately. Simply
deduce what available security mechanisms would provide the most

reasonable, cost-effective, and efficient solution for a specific
environment and situation. However, all security mechanisms must be
weighed against the value of the objects they are to protect. Deploying
countermeasures that cost more than the value of the protected
objects is unwarranted.