Ceied, I dont think you can't just run anyones license as far as a few cops I know tell me. They need to log the reason they run a plate just for that reason.....Hot chick in a car, what's her name and age....
I'm sure some will still do it but we used to have WCCA in Wisconsin where you could log on and search someones name and birthdate or just the name and get back all court time spent including divorces and arrests.
Also you could try watching old episodes of DATELINE Predator....A sure sign not to hire them.