Thinking about this, if the state wanted to really fuck you over with a milage tax, they'd do it every time you register your car. Make you pay a flat rate to see about also registering your car as well as making sure you smog. Checking your current milage vs what your last registered date was.
It's fucking scummy that the thought of it was even made up, and wouldn't even surprise me with commiefornia. Glad I left when I did.
As a reminder, get the fuck out while you can brothers.