How funny to come across this thread just a few days after I improvised a seatback organizer of sorts on a long overseas flight, by clipping a small bag to the seat pocket using a carabiner clip. It was a handy way to keep a pack of tissues, glasses, lens drops, meds, small tube of hand cream, and other little comforts right at hand. I had a window seat, and it was clipped on the window side so it didn't bother any other pax, and the structure of the seat pocket let me attach the clip without damaging anything. It worked so well, I'm sorry I never thought of it before.