When Principal Skinner introduces Adil to the school in the auditorium, the American flag can be seen in the background. It is hanging incorrectly as the proper way to hang the flag in that fashion is to have the blue field of stars in the upper left corner not the upper right as displayed here.
During the entire scene in which Principal Skinner discusses the student exchange program with Marge and Homer, the house layout is incorrect. The scene takes place in the living room and in the background, the dining room and the family room have switched places with each other. Thus making the front door and the back door seem to be on the same side of the house, which is incorrect.