12 in an Islander (Brumm Brumm) is no big deal. Haven't operated in PNG since the early '80s but it would have been unusual then not to have high density seating. Thats 4 rows of 3 abreast bench seating plus front right seat and legal to have a babe (picaniny) in arms. For a child it was legal to have two of them in one seat belt. Do the maths. That was a lot of kanakas on board and all legal. Just make sure they are all strapped in and weight OK and you are good to go.