Speed Checkpoint for teenagers

An 18 yr old High School student has come up with a device called "speed demon" which tracks the speed of teenagers through a GPS device attached on their vehicle. The device would alert the parents only if the vehicle exceeds the threshold limit set in the device. The privacy of the kids (the place they visit / travel / stop at etc) cud be maintained if they travel within speed limit. It is a situation of - lose privacy if u disobey - !!