In only a few years, the surveillance start-up Flock has installed more than 100,000 licence plate reader cameras across the United States.
But a grass-roots movement upset over privacy concerns is fighting back – even going so far as systematically vandalising the equipment.
The first time he decided to trash one of the cameras, a self-styled vigilante wearing all black and known as Nomark, says he was “super nervous”.
Now, after disabling about 30 of the devices near his home in the Minneapolis area, he said: “I’m not really as scared any more.”
Flock cameras are installed by police departments, homeowners’ associations and businesses, ostensibly to catch criminals in the act. Data is uploaded to Flock’s cloud and can be shared with subscribers.
But opponents are outraged at what they say is a dangerous tool that can be used to infringe on American privacy and civil liberties.