What role do airport employees play in enforcing security measures?

Airport employees play a crucial role in upholding security measures by being vigilant and adhering to established security protocols. Their responsibilities include monitoring individuals' behavior, identifying suspicious activity, and reporting any potential threats to security personnel. Additionally, employees are trained to enforce access control measures, ensuring that only authorized personnel have access to restricted areas. This proactive approach is essential in maintaining a safe environment for both passengers and staff.

The other options relate to functions that, while important, do not specifically focus on the enforcement of security measures. Providing transportation for passengers pertains to customer service, handling complaints and inquiries addresses customer relations, and performing maintenance on security equipment is a technical role that supports security but does not directly involve active security enforcement. Thus, the emphasis on vigilance and adherence to protocols distinctly highlights the fundamental role that airport employees play in security.