Pretty inventive. Since the registration fee is $46 it wouldn’t rank high in the annals of tax evasion. The big tax, like the sales & use tax, would have been paid to the dealer upon receipt of the vehicle so there wasn’t any evasion of the sales tax. Also, by leasing a new vehicle every 6 months he was basically paying two times the sales tax on the car every year.
Sounds to me like he was pretty heavily subsidizing the California DMV, not cheating them out of anything.
You don’t have property taxes in Cali?