In California, at least, if you are a resident of the state, you are legally required to register cars garaged in California with the California DMV. (It's actually a little ambiguous in an annoying way; even if you have a car that's garaged out of state, simply bringing it to CA for a weekend and driving it around can potentially trigger the CA registration requirement, again, assuming you are a CA resident.)

I'd be surprised if most other states don't have similar vehicle laws.

And the CHP has a website where you can report violations.

I hear you bringing up 2 separate actions that can trigger a registration requirement.

1) Garaging a vehicle, for x days or more.

2) Driving a vehicle, for x days or more.

Have you looked into what the specifics are, and how they are triggered?

Poking some holes at this:

- Are you on the hook to register vehicles you don't own for actions (1) or (2)?

Consider two examples:

(a) you rent a vehicle,

(b) you drive or choose to house a friends' vehicle.

From what you've stated, logically, anytime you rent a vehicle or operate or house a friends', you now are asked to register it.

Do you think this is accurate? And if so, do you think it would hold in court of law?