Reminds me of being a junior engineer doing radio signal measurements before and after a network optimisation.

With slightly worn hi-vis shirts, clipboards and our portable RF spetrum analyser, we got into all sorts of places from airport lounges (pre 9-11), F1 racetrack a few days before the big race to hotel suites and several corporate office buildings. We were always polite and asked permission before entering private property, but not once did anybody check our IDs nor call to confirm our story.