I've had that happen to me before.

I was at school waiting for my next class to start. I wasn't really paying attention and this girl yelled out my name. I didn't think they were calling me since I have such a common name but it's instinct to look up.

She comes over and starts talking to me, asking me how I am and how I like school so far. I just went with it. At first I thought she had mistaken me for someone else (I had a sweatshirt with my name on it) but she told her friend that we went to high school together and she said the name of our school.

So weird.