Travel between B.C. and Washington state was not documented in the 1960’s so if Ann Dunham came across the border as the passenger in a car in August of 1961 there would be no record of it! When a car approached the boarder between the two countries they would stop, a border guard would ask the nature of the visit and as often as not simply wave the car and passengers through without even asking to see any documentation. If they did ask for any documentation they would ask to see the driver’s license but they paid no attention to the passengers at that time! I experienced this many times in the 60’s as did other Freepers.
It was like that when we went into Canada in the 80’s. Just drove through the gate, answered a few questions and did the same on return.