Airlines don't sell a seat they sell the transportation between 2 airports (see their T&C's) to an individual. However ff you want an extra seat for extra-room

Airlines don't sell a seat they sell the transportation between 2 airports (see their T&C's) to an individual. However ff you want an extra seat for extra-room there is a procedure (usually use "XS" as your middle name or ExtraSeat as a first name). He didn't do that, he created fake identities...