As many as four San Francisco cops handcuffed and held a woman at gunpoint after failing to check the accuracy of a vehicle-mounted license-plate reader, which misread a number.

Given that situation, a federal appeals court on Monday reinstated that woman's civil rights lawsuit . The Ninth US Circuit Court of Appeals cried foul on the San Francisco Police Department's claims that it was a reasonable traffic stop, despite the officer failing to notice that the woman's license plate was different from the one the electronic reader flagged as stolen.

Furthermore, the plate read by the electronic reader belonged "to a car with a different make, model and color" than the 1992 burgundy Lexus ES 300 the 45-year-old African American woman was driving, the court noted.

The bungle is the latest example of the fallibility of license plate readers as they proliferate among law enforcement agencies, and it highlights that officers and police agencies are relying on them instead of good old policing instincts. Just last month, a similar situation happened near the border of Kansas and Missouri, when an electronic reader misread a license plate.

The woman in the San Francisco debacle, Denise Green, will get her day in court unless there's a settlement, the appeals court wrote.

A lower court judge, in initially tossing the suit, ruled that officers made a "good faith, reasonable mistake" and that "no reasonable jury" would conclude that officers "lacked reasonable suspicion to conduct an investigatory stop."

At the time, there was no SFPD policy requiring officers to verify that a license plate of a vehicle actually matched the license plate number that an automatic license-plate reader flagged as suspicious. Green's license plate number was 5SOW350. The electronic reader read it as 5SOW750.

The woman was handcuffed, searched, and forced to her knees for about 20 minutes. She was held at gunpoint by the officers, one even with a rifle, in 2009. After the cops discovered their bungle, they let her go shortly before midnight. She filed suit.

The appeals court noted that police quietly followed the woman for some time, even stopping behind her at a red light. But they never bothered to compare the victim's license plate to the one the electronic reader reported as stolen. The court concluded that a jury might find excessive force was used, as Green was "visibly unthreatening" after being pulled over.

"During a portion of the time that the officers pointed their weapons at her, Green was handcuffed and secured; moreover, she weighed 250 pounds and was barely able to rise from her knees without assistance," the appeals court noted.

On appeal, San Francisco police authorities argued that the belief that the vehicle was stolen, "in and of itself," justified the amount of force used during the stop.