Inside the growing vigilante movement to knock out Flock surveillance cameras

An underground network of privacy activists is disabling or destroying the ubiquitous surveillance devices sprouting up across the US

The first time that NoMark" tried to knock out a Flock camera feed, he waited an hour for the perfect moment - pacing in and out of bushes that towered over him, a few feet behind a pole holding up the device.

I was just so nervous," he said.