Given that Washington appears to be a police state, we may be splitting hairs. As Galt reads the state regulations, the owner of the establishment may request identification, but is not required to do so.<quoted text>
In this state if you are politely asked for ID on a drinking establishment and you politely refuse to offer said ID you will be politely asked to leave. If you refuse you will be ordered to leave. If you refuse the authorities will be called. You will leave, one way or the other. Remember the business has the right to refuse service. You have no right to be on others property if they do not want you there. The owners do not have to surrender their rights.
In the long run, tavern owners who act like a-holes will go bankrupt.
Your bigger problem may be importing liquor. If your cousin in Portland gave you a bottle when you visited over Christmas and you brought it back to Washington, you may be guilty of a serious crime.