This is easy enough to test yourself, download for example the nrf connect app for mobile: then scan for bluetooth addresses in the app. You will have to remove all phones/gadgets from the test person and ideally go somewhere where aren't a lot of signal. If you see a potential unidentified bluetooth address, you can check the RSSI value to see if the signal getting stronger as you move your phone closer to the person.
This is easy enough to test yourself, download for example the nrf connect app for mobile: then scan for bluetooth addresses in the app. You will have to remove all phones/gadgets from the test person and ideally go somewhere where aren't a lot of signal. If you see a potential unidentified bluetooth address, you can check the RSSI value to see if the signal getting stronger as you move your phone closer to the person.