I would zip-tie the pole to the seat back's frame. Small zip-ties would go through the meshing holes without damaging anything, and you wouldn't feel them behind your shoulder. As for the flag, if you want to fly country flags, a great place to find good quality flags of all countries in all sizes, often with a halyard mounting cord sewn in, is a marine shop. When I tour abroad, I always fly my country's flag. If I know it rubs on the locals for whatever reason, I replace it with a dayglo triangle, so as to not get nasty remarks or punches in the face.