When "Perfect Fairness" Stops Everyone
■ Correctness That Causes Dysfunction Faced with simultaneous requests, a robot's honest instinct is to arbitrate fairly. In Episode 41, the moment Oshiro and Terashima called him at once, Hakobukun halted mid-corridor and displayed "Calculating priority…" Comparing every variable to find the optimal answer is algorithmically faithful—but that faithfulness keeps both nurses waiting.
■ The "Midpoint" as the Worst Landing Unable to finish, Hakobukun displayed "Fair mode: waiting at the midpoint" and stopped between them. Mathematically perfect fairness, yet the worst lived outcome—satisfying no one. In HRI, arbitration cost can exceed the value of fulfilling a request. Equal disadvantage for everyone is fair, but not useful.
■ Conclusion: The Speed of Simple Rules The answer is the nurses' unison line: "Just go first-come, first-served!" FIFO sacrifices strict fairness for instant resolution. Perhaps the designer's job is not to write perfect arbitration logic, but to design where to give up arbitrating.
