Some areas of the country do throw the weight in youth competitions. If you or one of your athletes is scheduled to throw in a youth meet, you will need to contact the meet director and check what size weight they will be using for the age group.
In the sense of performing as designed, most radar detectors do detect the presence of police radar in the immediate vicinity of a speeding vehicle. Whether or not that information will actually prevent a driver from receiving a speeding ticket remains to be seen, however.
A radar detector is a driver's best friend. The advantages that it gives a smart and responsible driver cannot be overstated, but most people are wary because they're unsure of the device's legality. The US's fractured state regulations compound this problem, especially for long-distance drivers.