They never told him anything. Never. They just expected him to know what was going on, without any sort of indication of what they were doing. They just expected him to know that they had invited the Gantorian ambassador on the flight. Nor did he know that the ambassador was the green-skinned fellow with the over-sized bag that wouldn’t fit in the overhead bin, and nor did he realize that the fellow would be a total jerk about checking his bag. So, when he’d called security, and it turned into an inter-planetary incident, he had PLENTY of people to blame.