I screen hard enough not to be surprised when I open the door, but I have had people I know inquire before and I won't see them. Even if they're cute, there's just too much potential for things to get awkward.

Never happened with a provider, but it did happen twice at 2 different strip clubs. One lady was someone I worked with, and the other was someone I had gone to high school with. It was a little awkward at first but they were both hot so I got over it. LoL

Once I visited an ex coworker unknowingly  
... I did not recognize him but he did me and told me about half way through ... I wanted to leave but he "begged" me to stay and said it was a huge fantasy of his

Not me but a favorite lady once told me she was well into a meeting when the guy said "I know how I know you, I was your son's sixth grade teacher"  

I presume that the realtor was able to deduce that you are the real you based on your photos/ads/etc so going into it he probably knew that connection already?  Was that the case?