They don’t enforce front plates much in SD but they do up in LA. A friend of mine used to commute between here and Pasadena and got hassled about it all the time. When he bought his next car, he decided to put NO plates on it. He just left the paper dealer advertising plates on and put the DMV plates in the trunk. For like three years he did this! When the paper plates started getting faded he’d go back to the dealer and ask for new ones.
He got stopped at one point and the cop, after looking at the registration and seeing that plates had been issued, asked why the plates aren’t on the car. My friend spun some long spiel (some of which was true but most of which was highly exaggerated) about how the plates arrived in the mail right when he was moving, they’d gotten lost in a moving box and they had just turned up last week, hadn’t gotten around to putting them on yet, they’re in the trunk I can show them to you, etc. Cop gave him a lecture but let him off without so much as a fixit ticket.
I was tempted to try the same thing but didn’t have the balls to pull it off. I’m a terrible liar and I’d probably blow my story.
