Automated license plate reader (ALPR) technology allows law enforcement officers to quickly recognize expired tags and identify and locate stolen vehicles. But it's also often instrumental in finding wanted and missing persons and solving a wide range of crimes, including homicides.
Although law enforcement officers are given considerable leeway for reasonable mistakes, you don't get much slack for unreasonable mistakes that result from hasty reactions to bad information that comes from your own official sources.
Many state legislators are listening to the ACLU and others who want to rein in LPR operations. New Hampshire already bans the use of the technology except at toll stations, and other states are considering legislation that to some degree would change the way agencies use LPR.