Alaska Airlines has a rollout status of 'installed' with a high fleet coverage ratio of 72.2%. Despite zero observed flights with confirmed Starlink on the CHS->SEA route, the critical scoring rule mandates that the probability cannot be below the fleet coverage ratio for airlines with installed status and fleet coverage above 50%. No recent news or community sightings affect this route specifically, so the probability is anchored at the fleet coverage ratio of 0.722. Confidence is medium due to the lack of direct route observations but strong fleet-wide deployment data.