St. Louis Today reported: When is the line crossed between better health and surveillance? In early 2012, wristwatch-like devices called Polar active monitors will be used by older students in PE classes at all 18 Parkway elementary schools. District officials say the devices should help improve the students’ fitness and academic achievement. Later this school year, the district plans to collect data about activity levels and even sleep patterns for a week at a time. It will have the students wear the devices round the clock. Some parents and legal experts are raising privacy concerns about at least that aspect...