Steve Chapman: Put not your trust in surveillance cameras

Video surveillance cameras have been growing in popularity for years, but in recent weeks their advance has gotten a turbo boost. After helping to identify two suspects in the Boston Marathon bombings, they went from occasionally desirable to universally vital.

Mayor Rahm Emanuel of Chicago, which already has some 10,000 cameras, said the city would keep on adding cameras — perhaps outdoing his predecessor, who dreamed of a camera on every corner. New York Mayor Michael Bloomberg took a similar tack: “You wait — in five years, the technology is getting better, there will be cameras every place.”