Beth Widner is a mother who lives in Canton, a middle-class suburb of Atlanta, Georgia. She has four kids, whom she homeschools while her husband, Glenn, telecommutes. In August of 2018, the Widner kids—then ages 13, 11, nine, and seven—were members of a swim team at their local YMCA, which was about two blocks from their house. One day, after swim practice, the 7-year-old, Jackson, lagged behind while the rest of his siblings walked home, and stopped by the grocery for a free cookie. A store employee thought it was so unusual to see an unaccompanied 7-year-old that a store...