I was one of those tourists many years ago. A group of us Californians wanted to conduct an experiment: What would happen if we stood on a corner and just said "Hi!" to people. OHHHHH, the looks we got! On guy gave us a strange look and said, "Oh, you must be from California!" Dang, was it THAT obvious?
Around here, people would just say 'Hi!' back at you.
They'd also probably comment to each other on how nice you were.