California flatly requires front license plates, and has for as long as I've had any acquaintance with the place. However, the law has a long history of being enforced only locally or sporadically.
Several years ago I did a highly unscientific survey of some parking lots near my home and workplace and concluded that about one California car in eight had the front plate replaced with sports-team merchandise, obscured by optional equipment, or just flat missing. Some sporty models didn't even seem to have a place to put one.
Every once in a while some jurisdiction has a burst of enthusiasm for (dismissed if you pulled into the local cop shop and showed that the the wayside one or two cycles of budget woes ago, so this and other equipment violations are now likely to cost cost hard money.
Why the airport police are doing it, I dunno. Perhaps it's a convenient revenue stream that they can tap since they're supposed to be scrutinizing cars more closely for security reasons anyhow. Maybe somebody elsewhere in the state government asked them to do so. Maybe they concentrate on cars that they want to look at more closely, or whose drivers have exhibited "contempt of cop." Maybe it's because they can (and it is after all a violation, though not one that we normally expect that variety of cop to go after).
I suspect that photo-radar and red-light cameras are among drivers' many possible motivations for removing the front plate.
How useful it would be for crooks to steal the front plate, I don't know, since the fairly visible and all important registration sticker appears on the rear plate only.
See for instance and
Cheers, --Joe
