Noticed this on my seat neighbours boarding pass on my transborder flight last night.

Boarding pass said ML*5/C2 on the bottom.

The passenger's original seat was 12B, but it was crossed out in black pen and changed to 3F. No new boarding pass issued. Computers fully operational at the gate agents desk and other new BPs were issued for seat changes etc.

Passenger was called up to the desk by the gate agent prior to boarding and was spoken to. Passenger boarded plane towards the end of the line. There was no one sitting in 12B during the flight.

During meal service, when the Service Director was taking orders, passenger was not asked what they wanted. After taking orders, Service Director came over and said to the passenger "I have some dinner for you", and what the passenger was given was not one of the three options offered for dinner that evening (could be a special meal, hence the ML*5 designation, but the passenger was originally in Y, where there was no meal service to begin with (domestic flight) so the boarding pass meal designation would not have applied as it was B.O.B.).

My hypothesis was that the passenger was the suppose /friend/family of the first officer, as the first officer chatted with the passenger from a distance while waiting in line for the washroom (unless the first officer was just a very friendly individual who enjoyed making random conversation while waiting for the washroom). Any thoughts?

Also on board in J and seated in 4A, a fully uniformed non-deadheading FA (at least that is what the FA said to the SD when inquired if she was deadheading).