Explanation/Reference:
Explanation:
Protective switch covers would reduce the possibility of an individual accidentally pressing the power button on a device, thereby turning off the device. Redundant power supplies would not prevent an individual from powering down a device. Shutdown alarms would be after the fact. Biometric readers would be used to control access to the systems.

Explanation
Risks are constantly changing. A previously conducted risk assessment may not include measured risks that have been introduced since the last assessment. Although an assessment can never be perfect and invariably contains some errors, this is not the most important reason for periodic reassessment. The fact that controls can be made more efficient to reduce costs is not sufficient. Finally, risk assessments should not be performed merely to justify the existence of the security function.