Wow that seems crazy to me. I grew up in the northeastern US where even 3 decades ago, before a large expansion, we had 7 area codes within an hour drive. It would be bizarre to make such an assumption about someone, even then. When I lived in Boston, there was tons. Eastern Massachusetts alone has 339, 351, 508, 617, 774, 781, 857, and 978 as local area codes.