Southwest Airlines is currently in a rolling_out status with a high fleet coverage ratio of 86.2%, which normally would anchor the probability near this level. However, there are zero observed flights with confirmed Starlink on the BNA->MEM route and no recent news or community sightings to support a higher probability. The perplexity context indicates no aircraft currently equipped, with rollout expected to begin in summer 2026. Given these factors, the probability is conservatively anchored at 0.30, treating the fleet ratio as a floor but not exceeding the empirical observation rate by more than 0.10 due to lack of direct evidence.