Kathy, having gotten the dreaded SSSS on her boarding pass, had to go downstairs so a polite official could check her possessions more carefully, but it was an innocuous procedure.
There was a significant delay in boarding, which we were told was due to a shortage of cleaning personnel. We heard another explanation as we finally boarded; the jetway wasn't working properly. We had to walk downstairs, walk across the tarmac to the plane, and then climb the significant distance to enter.
Immigration was a relative breeze at SEA, and we were soon waiting for a pickup from the Doubletree.