Final answer:
Open guest Wi-Fi is not useful for managing visitors in a secure facility as it could compromise security, unlike Biometric access controls, Visitor badges, and Security cameras that aim to control and monitor access.
Step-by-step explanation:
Among the options provided, Open guest Wi-Fi is NOT useful for managing visitors to a secure facility. Items such as Biometric access controls, Visitor badges, and Security cameras are specifically designed to control and monitor access, ensuring that only authorized individuals can enter sensitive areas and their movements can be tracked.
Open guest Wi-Fi, on the other hand, could potentially compromise a facility's security by allowing unauthorized access to the facility's network. This could lead to data breaches or the introduction of malware. Therefore, it does not contribute to the secure management of visitors within the premises.