Not sure if this guy was a scammer or just a bit clueless. I was working last Friday, and the office was almost empty because it was a Canadian long weekend. The doorbell to my floor rang (you need to ring the bell if you don't have an employee badge). When I answered it, a somewhat scruffy fellow said "I was told to come to 123 Blah Street to pay my bill." I said "Uh, this isn't Blah Street. It's Yadda Yadda Street." "Oh, did I say Blah? I meant Yadda Yadda. 123 Yadda Yadda Street." "This is still the wrong place. This is 456 Yadda Yadda." "Oh. Then I have to go somewhere else?" "Yup." Whereupon he left.
There was something about the way he quickly said "Oh, did I say Blah?" that raised my red flags. I started mentally reviewing how many people were left in the office, and whether or not they'd hear me if I had to scream. Luckily, it didn't come to that!