Driver's license photos have audited lookups, but all that tells us is that the system is routinely abused and no one is stopping it. http://www.wired.com/threatlevel/2012/02/cop-database-abuse/

Putting every car into the database will generate the maximum number of conflicts of interest possible. If a database only has interesting or suspicious plates in it, an average cop might not browse the database for funsies (risking a hit on the next audit). But if everyone the cop knows is in there, they might check up on spouses, exes, cute girls' habits, old bosses, friend's bosses... the list of reasons to risk a peek is endless.