I lived in the SF Bay Area for about 40 years due to work. As far as I know, Ca. Has always considered a "pickup truck" a commercial vehicle. I remember asking a CHP officer one time about it when I was driving my dad's 72 GMC C15, and was told that if you carry ANYTHING in the bed, it is considered a commercial vehicle. That applies to your own suitcase. So, 2 choices. 1. Risk having non-commercial plates and getting zapped with a huge fine, or 2. Suck it up. All for the privilege of living there. For me, it ain't worth it.