4S schools are newer and nicer. In addition, the kids from Bernardo Point can walk/bike to 4S schools (the elementary and the high school in particular, the middle school is probably too far). Their new schools are miles away.
Also, The parents might be worried that the property values will go down. Almost every Bernardo Point ‘shelter for sale’ ad has the ‘enjoy 4S facilities without paying 4S MR’ line.