I fly once or twice a year from Hawaii to the mainland, almost always on red-eyes. On my most recent trip, the FA moved a passenger up to my row from the row behind. The two remaining people behind me stayed seated next to each other on the window and middle seat. The person who moved to my row was eating loudly much of the time and kept her reading light on. This was the only time in over twenty five years that a FA moved a passenger to my emptier row. I was upset - I think it is the luck of the draw to have an empty row. Noting rude about protecting your space.