I don’t think they do regular inspections in CA, except at title transfer. And anyway, VIN is not at issue here, they’re saying if an individual component in the car has no serial (not has a stolen one, but just a missing one), it justifies seizing the entire car.
I see what you’re saying. And I can’t imagine cops can be bothered with checking serial numbers on transmissions, blocks etc. Is there something omitted from the story?