Unscheduled visitors no longer are allowed in Lewisville (Texas) district schools while classes are in session. The district initiated a rule prohibiting drop-in visitors from entering a campus during school hours in response to an incident last week at Creekside Elementary School. The case involved a former student who district officials said dropped by unannounced to visit his former teachers and left the campus with a 9-year-old girl. The policy change does not affect parents of students at the school.