According to an article posted by Todd Quinones of cbsphilly, the Cherry Hill Police Department is now equipped with a new technology that scans license plates and searches databases to find wanted persons and/or stollen automobiles. A small machine, which can stand alone, is typically built into police cruisers. As cars drive by, the machine scans and runs the plates and checks to see if the owner has warrants or is connected to crimes. Recently, the scanner helped police find a man named Robert Ford, a robbery suspect connected to 8 crimes.
While the technology can find suspects of serious crimes, they can also check simple things such as expired tags. There is a privacy issue at hand that seems like it could get obtrusive and out-of-hand to the typical citizen whom isn't being investigated in a crime. The Cherry Hill PD claims that information isn't kept about non-criminal persons.
As long as government agencies don't start crossing-the-line with implementation, I see this as a good technology, because it's a fast-acting option for finding suspects and/or victims of amber alerts (kid-napping).