We have exactly the same problem in the U.K. especially London where the mayor was threatening to erect notices warning parents of photographers, especially those with digis and mobile phones. The 7/7 suicide bombers in London seems to have persuaded the authorities that a mass of people taking photos may produce useful information in such situations. If the mass of a city's population take street photos constantly it's then equivalent of CCTV cameras on every street which is where we are heading anyway.

Presumably 24hr CCTV taking pictures of kids is OK provided it is in the right hands, that is to say the authorities in which the populace can have total faith. This rings a bell. Ah yes, it's the nightmare scenario in George Orwell's famous novel 1984.