California, and hence Los Angeles, law does not require dealers to affix temporary tags to the outside of the car like some other states do. This means that the car appears to have no tags on the front and back of the car as would be expected. Instead all the dealer has to do to remain legal is to place the temporary registration document in the lower right hand area inside the windshield. It is speculated that dealers drive these cars to show they are brand new as a marketing ploy.
The temporary registration document can be used until the new plates arrive from the DMV, or for 90 days, whichever comes first. You must notify the DMV if the plates have not been delivered during this period. There are probably so many no tags Los Angeles cars on the road because of the number of just-purchased vehicles that are waiting for their plates to arrive.