What I know about the state of Wshington is that if you are living in this state for more than 30 days, you have to transfer your vehicle registration and apply for a Washington state drivers license. If you don't you face heavy fines cause if you maintain your Oregon Drivers License you don't have to pay the states sales tax when making purchasing taxable items.
One person in this RV Park has a 37 foot 5th-wheel, a mini van an a pickup truck to pull the trailer with. All three vehicles are registered in the state of Oregon and they have been living in this RV Park here in Cowlitz County for more than three years. Not having to pay state sales tax on anything they but from a to z that is taxable.
The state sure could make some money on this person and affew others with out of state registration on their vehicles.