Actually that's kinda creepy if you think about it. He could have called you first. But all is well that ends well.
How would he have called me? I didn't know him before today.
I was mowing the front lawn spring last year just wearing shorts and flipflops. Sweating up a storm. A local cop passed by in his cop SUV. He turned around and parked in the shade and watched until I finished mowing. Then he left.
Bothered me for a couple days until I put two and two together. 
I still haven't figured out what 2+2= in this case.
Seems a little odd that a cop would invite himself to your brew session...but as you said he was a homebrewer as well and was just curious. Perhaps taking it for face value is reasonable. I assume he was on duty?
He was on duty but at the end of his shift, running an official errand in my neighborhood (which is not in his jurisdiction). He didn't exactly invite himself, he asked if I minded if he came up the driveway, he admired the setup, told me he brewed a batch of old ale yesterday, we talked Randall's, mills, NHC, etc. He stayed for a while. There was nothing creepy about it, it was friendly and when I start talking about beer I can keep going for a while. If he had been out of uniform I would have been pouring him samples.

Cool, I keep hoping some of my 'unknown' neighbors would stop by but
they don't.
This is the same way I feel about it. People drive by and stare but rarely stop to talk. I need more people to drink my homebrew so I have an excuse to brew more.
