License plate readers, or license plate readers connected to a real time database of DMV and criminal data? I ask because ALPR's are very common now for consumer surveillance cameras and very affordable. Anyone could install one and just not tell anyone. If I so desired I could log every plate going up and down the highway and so could anyone else.

Now if I could connect my system to a real time API and detect stolen cars or cars belonging to wanted felons that would be the bees knees. It would not even have to disclose names or crimes, just 0 or 1.