The California Highway Patrol is asking local drivers to report people they know are living in the state but driving with an out-of-state license.
It even has a website called Cheaters: Out-of-State (Out of State Registration Violaters).
The CHP says the state of California, "loses millions of dollars a year in revenue from California residents who unlawfully register their vehicles in other states or countries."
Somebody moving to California from out-of-state has 10 days after establishing residency to get a California driver license and 20 days to register his or her vehicle.
That can be complicated when booking an appointment at the DMV, which is a requirement for getting a driver license. Appointments at some DMV locations are backed up for several weeks.
The DMV has plenty of information on its website, about what documentation is needed for obtaining a license and registration.