A guest engagement system and associated methods provide seamless engagement with guests of facilities through the use of wireless sensing technologies. The system makes use of individual guest devices which are carried by guests and used to automatically identify and authenticate the guests throughout the facility. Services can thereby be seamlessly provided to the guests throughout the facility. The services include contact tracing, automatic unlocking of doors, including hotel or state room doors, based on the guests' immediate proximity to their assigned room's door. The services also include automated payment services provided at checkout or vending terminals, and automated log-on to interactive displays and portals, among others, based on secure wireless authentication of the guest devices. The guest devices can each include a device health sensor configured for measuring at least one health function of a user wearing the guest device.