What Happens When Police License Plate Readers Make Mistakes?

An anonymous reader writes:
The Verge reports that San Francisco Bay Area police "pulled over a California privacy advocate and held him at gunpoint after a database error caused a license plate reader to flag a car as stolen, a lawsuit alleges." Brian Hofer, the chairman of Oakland's Privacy Advisory Commission, was handcuffed and surrounded by multiple police cars, and says a police deputy injured his brother by throwing him to the ground. They were finally released -- 40 minutes later. But ironically, Hofer has been a staunch critic of license plate readers, "which he points out have led to wrongful detentions, invasions of privacy and potentially costly lawsuits." (California bus driver Denise Green was detained at gunpoint when her own car was incorrectly identified as stolen -- leading to a lawsuit which she eventually settled for nearly $500,000.) And at least one thief simply swapped license plates with an innocent driver.

The executive director of Northern California Regional Intelligence Center, a state government program, acknowledged that the accuracy rate of the license plate readers is about 90 percent, yet "added that in some cases, the technology has actually exonerated people, or given potential suspects alibis. But there is no way for the public to know just how effective the license plate reader technology is in capturing criminals" -- apparently because police departments aren't capturing that data. Only one of the region's police departments, in Piedmont, California, reported its "efficacy metrics" to the agency -- with 7,500 "hits" which over 11 months led to 28 arrests (and the recovery of 39 cars) after reading 21.3 million license plates. The license plate readers cost $20,000 per patrol car.
In Hofer's case, he was driving a rental car which had previously been reported as stolen but then later recovered -- though for some reason the police or rental car agency failed to update their database. But he criticizes the fact that "somebody could pull a gun on your because of an alert that a computer system gave them."

"They're just pulling guns and going cowboy on us," Hofer says. "It's a pretty terrifying position to be in....

"This is happening more frequently than it should be. They're not ensuring the accuracy of their data and people's lives are literally at risk."