He made up a reason for acquiring this ship under his name that was difficult to distinguish as true or false in a short time. Since communication in this world isn't very advanced, he could easily mention the name of a distant friend, and these naval inspectors couldn't possibly fly over immediately to confront them. Moreover, he understood the rules quite well. Besides having elaborate disguises, he was also well-versed in this line of work's unspoken rules. During the conversation, he stealthily slipped a luxurious golden insignia into the inspector's hand without anyone noticing.
"Your Excellency Inspector, this is an exotic souvenir sent to me by an old friend, but I don't understand its artistic value. You're experienced and knowledgeable, surely more fit to appreciate its charm..."
