Windows 10 has rudimentary facial recognition but fingerprint scanners are more secure. The best security is a password. Large scale databases used by law enforcement have been discovered to have a huge false positive rate. The same for license plate readers which also are notoriously unreliable.

The reason facial recognition is uses is due to its passive and non invasive nature.

Work in facial recognition goes back to the 1960s as mainframe computers became available. It was realized early on that many problems existed such as face angle, lighting and even aging.

3D sensors to capture information about the shape of a face. This information is then used to identify distinctive features on the surface of a face, such as the contour of the eye sockets, nose, and chin. One significant advantage of 3D face recognition is that it is not affected by changes in lighting like other techniques. It can also identify a face from a range of viewing angles, including a profile view.

A more modern approach to 3D is to use 3 cameras at different angles. The cameras provide the computer with multiple images from which to ascertain the 3D components.

Facebook has been able to reach 97% accuracy using 4 billion user images. The FBI system only manages 85% accuracy. Facial recognition software is particularly bad at recognizing African Americans and other ethnic minorities, women, and young people, often misidentifying or failing to identify them, disparately impacting certain groups.

In the US the PIN is protected by the fifth amendment. Courts have considered a finger to be like an ordinary key. Facial recognition is still a legal grey area.

At protests police use facial recognition in violation of the right to free speech. The death of Freddie Gray led the Baltimore Police Department to run social media photos through face recognition to identify protesters and arrest them. Ohio now has a face recognition policy expressly prohibiting the use of the technology to track individuals engaged in protected free speech. 

Nolle prosequi means decline to prosecute or stay of proceedings. Rule 48 now mandates that prosecutors seek leave of the court before they dismiss a case via filing a nolle prosequi.

The City of Baltimore settled with the Grey family for $6.4 million rather then have them spends years in litigation which is reasonable given the matter of the death of Mr Gray.

The problems may pressure more regulation but the process is very slow. The congress has to do something.