I have an email address that is every bit as silly as my username on HN (i.e. something that I didn’t think could ever be entered by accident), and yet a man na

I have an email address that is every bit as silly as my username on HN (i.e. something that I didn’t think could ever be entered by accident), and yet a man named Sean from Michigan (I’m British) is signed up to AAA with my email. I was actually able to Google the combined information included in the emails over the past couple of years to pin down the guy’s home address. I did consider sending a postcard explaining the situation, but balked at the idea in the end, in case it came off more creepy than lighthearted.