Bullied him until he confessed? Probably using police tactics: "We can see you used Skiplagged", even though they can't really. "We'll go easy on you if confess, buy another ticket, and we'll ban you only for 3 years as opposed to for the rest of your life!".

I've seen TSA and airline workers in various airports get their sadistic pleasure out of bullying people. I'll always remember watching helplessly as they forced my elderly parents to the side, for the "extra" security check, all while making fun of them not speaking English well, and laughing at their visible distress and confusion. It's the little bright stop in their day to fight the monotony, low pay and boredom.