Which excerpt from Nadine Gordimer's “Once Upon a Time” best indicates that in trying to ban “these people,” “such people,” and “thieves” from the neighborhood the family has made themselves prisoners in their own home?

But to please her…--he had electronically controlled gates fitted
The little boy was fascinated by the device and used it … in cops and robbers play
So from every window and door in the house…they now saw the trees and sky through bars
They sat about with their feet in the gutters…--for it was a beautiful suburb, spoilt only by their presence