Originally Posted by
stringandrudder
Yeah, I get that. But that's not what happened. It hadn't gone down the jet bridge yet to the airplane. I simply walked back out of the airplane to the bridge and took the bag which was waiting to go down, onboard as a carry-on
Did the bag have a check tag on it? If so it was checked luggage and is tracked through the system with tag readers. By taking the bag out of the jetway and pulling the tag off, the airline now has a "lost" bag. So, bags in at the departure airport won't equal bags out at the destination airport (according to the computers).
The other aside is that traveling as an unaccompanied companion, you're representing your sponsor who's responsible for your conduct. This isn't the worst offense in the world but certainly something to think about. How would it feel to cause your sponsor to lose travel benefits (or worse).