This verse repeats from Judges 18:7 that the people from Laish are a people quiet and unsuspecting.
The repetition of these details about Laish’s peacefulness and unsuspecting character on account of their isolation is to underline their status as victim.
27 But the people of Dan took what Micah had made, and the priest who belonged to him, and they came to Laish, to a people quiet and unsuspecting, and struck them with the edge of the sword and burned the city with fire.