When I worked IT, I went to a local fire station and said I was there to update their computers. The person I talked to didn’t seem to know that this was scheduled, but they led me to their office with the computers and showed me how to log on. I’m pretty sure they just assumed I was telling the truth because I spoke confidently and was wearing a polo, but I could have literally been anyone.
Don't even think about it (startrek.website)