After reading the therms and KWH on your PG&E bill, they would send out an inspector to "help" you. Expect fines and perhaps jail time.
I'm not kidding. They think of fines as a revenue source.
That kind of thing happens all the time, already.
I did a 500sq. ft. addition to my house a few years back, and one of the criteria to get the Building Inspector to sign off was that my new bathroom had to have a fluorescent fixture. So, I went to Home Depot and picked up the cheesiest bathroom-lookin fluorescent piece of junk I could find, brought it home and installed it.
The inspector came, looked over everything, saw that fixture, checked off the box, and signed us off.
As he was pulling away from the curb, I was back in the bathroom installing a new, three-lamp incadescent fixture that matched the rest of the decor. Then I went back to Home depot and got a refund on the fluorescent thing.
If this thermostat garbage ever gets into the code books, expect similar scenarios involving them, too. Buyers of new homes will make "Replace the thermostat" the first job they do BEFORE unpacking the boxes.