Seeing a KC-46 at Boeing Field is not necessarily such a surprise. However, seeing one parked up at the FBO was more unusual. I am not sure whether the aircraft had been accepted and was ready for delivery or had actually come across country for a visit. Either way, a USAF crew was about to fly it back across the country. The size of the taxiways meant that it had to cross the runway to taxi up to the departure end where it could line up and head off on its way east. Was it a delivery? Who knows?