Actually what was done in Ca. all had to be done there.
Who told you that?
I have bought several out of state cars, trucks and trailers. You do not register them (and pay the tax) in a state you don’t live in. This is from a guy that has worked in 19 states; I travel a lot. I currently have two vehicles I bought out of state. Neither were registered in the states purchased. I transferred both out of state titles in Texas where I live.
Louisiana tried something that required out of state residents to buy license plates and driver’s licensees while working in their state. Texas, Oklahoma, Arkansas and Mississippi won the case in federal court. Requiring you to register out of state (and pay the highway tax) is against federal interstate trade law.