Although

> Adding a camper shell to a pickup truck does not necessarily constitute a change from commercial to auto registration. The addition must meet the definitions for human habitation or camping purposes. Otherwise, the vehicle may be subject to citation from law enforcement for not meeting the definition of an auto. Human habitation is defined as living space which includes, but is not limited to: closets, cabinets, kitchen units or fixtures, and bath or toilet rooms.

. People do this all the time.

. The police never check.

You'd be surprised how expensive an old pickup's registration can be in CA.

The main problem isn't the cheating by low-end tradesmen but that the average schlub's truck is considered a 'commercial' vehicle including registration cost by gross vehicle weight. (at least that's how I understand all of this).

They never make it easy here to do anything, but people will put up with a lot of rules and taxes if it mostly happens to others.

This is how some people get away with registering commercial big rigs as not for hire and for towing their giant fifth wheels

I suppose they're wagering that the police won't do a detailed evaluation of the suitability of the space for habitation.