People make assumptions not only about a person's geographical origins, but potentially also their class background, from a giveaway twang or lilt, for example.
The people over the hill would have triggered the feeling because they were farmers while you were fishermen, or they spoke with a lilt in their vowels while your diction was monotone and flat.
The magic comes in a nervous trickle—Henry's tie, hopeful lilts in voices, a few stray bits of confetti that escape the nets laced through the rafters and get stuck in Nora's hair—and then, all at once.