His poise was perfect as he crossed the concourse with the highly vaulted ceiling. He moved with purpose but not in haste, his arms swinging freely, eyes straight ahead. At his heels, the squat, robot luggage-carrier dutifully followed the "bone" which he carried in his right hand. At the long baggage counter, the husky, human attendant took the "bone" and led the carrier under the counter through the low passage onto a platform scale. He whistled. "That'll be $4,175.00 excess baggage," he said.