What's with the CA license plates with "PCI" as the letters?

I seem to keep seeing on TV cars with California license plates that use “PCI” as the letters. E.g., a license plate like this:

4 PCI _ _ _

I’ve seen license plates like this on at least 2 different TV shows, one of them being “Life”.

What’s up with this? Did California allocate this letter sequence to TV shows? Is it just 1 license plate they keep swapping between cars? Did they register a bunch of cars all at once and just get “PCI”? (But then why on different shows? Actually, I can’t eliminate the possibility that the shows use the same production company.)

Has anyone else noticed this on different shows?

J.