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For Abraham, cameras are "not a guarantor that people won't commit crime. But it will give bad guys the notion, 'I'm going to be caught on surveillance tape. Maybe I won't do it. Maybe I won't do it today. Maybe I won't do it ever.' It's the same as a burglar alarm or any other thing you put up to prevent people from getting into your house."

How effective are the cameras? Allan Jiao, a professor and chairman of the law and justice studies department at Rowan University, said Britain may lead the world in the use of video surveillance.

By some estimates, as many as 4.2 million closed-circuit TV cameras observe the British, and the average citizen is caught by as many as 300 cameras a day.

But studies by the British Home Office show the cameras have mixed results, Jiao said. Some cameras only displace crime as criminals move outside the view of the lens. Other times, lawbreakers take advantage of the fact that not every camera can be monitored every second.

Still, the British keep adding cameras, he said.

"It makes the public feel better," Jiao said. "It simply makes them feel secure, and it's probably politically popular, as politicians can say: 'We're doing something about crime.' "

The ACLU's Frankel said relying on cameras to do an officer's work chips away at the relationship between police and the public they serves.

"We believe that community policing was a good move because it put police back in the communities and made them more connected to what was going on. To an extent, this is stepping back from that," he said.

Peter Crabb, a psychology professor at Pennsylvania State University's Abington campus, has researched how such technology affects both the watchers and those being watched. He has found that users "get used to invading people's privacy.

"It makes respect for individual rights sort of fly out the window."