I've lived in the northeast my whole life, and I don't remember ever being surprised at the idea of someone saying it. That's at least partially because I'm just used to the idea of people I interact with potentially not being from the northeast though. Even at a young age in the suburb I grew up in (with around 25k population, so not a particularly huge one), it was pretty common to encounter people who came from other states or countries. I guess if you're from a town small enough you might not be as used to interacting with people from other places, but is that really a regional thing or just a small town thing?