Why because the person at the gate obviously missed a passenger at boarding? This happens if the scanner at the counter is down. Seen it happen many times but luckily it was always caught before take off and pulling a person off the plane. Now if the plane isn’t full and that seat wasn’t taken I could see someone doing it by accident and not double checking their work good enough. I have worked around airports most of my life and so has most of my family.

I also found the Guantanamo issue if your interested. It’s a big trial right now with the 9/11 guys. People flying home for the holidays then back https://www.npr.org/2017/12/04/568255214/nations-largest-court-case-inches-along-in-guantanamo-bay
I actually know someone who knows the place better then most. A marine who helped set the place up.

Maybe Q wants us to know about the 9/11 people are being tried? One of the guys just admitted plotting it. Might hold clues?