Didn't use to be: back in the '70s, the CHP would pull cars over and sometimes even ticket them if they rode out in the left lane much below the speed limit (65, 70 or 75 depending on the freeway) and did not move over for faster traffic, and they would ticket cars in the right lane if they were under the freeway minimum speed (then 45 mph).
It used to be a mildly unnerving experience to be cruising down a freeway at 72 (no tickets given unless you were more than 7 mph over) and finding a CHP black and white come up fast in your mirror, having them flash their overheads at you, and then whizzing by accelerating towards 80+ when you changed lanes.
There also used to be a rule in California that if you had 5 or more cars lined up behind you on a two lane road where they could not pass, you had to pull over at the next turn out and let the others pass. On Highway 1, it was very common to see the CHP be the 5th car behind a slowpoke and, if they passed a couple of turnouts without pulling over, turn on the lights and ticket the first car. We always cheered when they did that!