Yeah, I do this. I don't like just passing time on a phone like many seem to, so anytime I get bored(lines, DMV, airport, airplane) I'll strike up conversation. Then again maybe I'm just a bit mentally unstable...
I personally love when people do that. I'm a homeschooling stay at home father, so I don't have a wide or close social circle; I thrive on those casual conversations.
It's normal most places in the US, not just the south. I've had plenty of light conversations with strangers in public spaces in the Northeast.