etiquette (n): conventional requirements as to social behavior; proprieties of conduct as established in any class or community or for any occasion. From

etiquette (n): conventional requirements as to social behavior; proprieties of conduct as established in any class or community or for any occasion. From the article, "The accepted notion is that such territory belongs to the person seated in front." Applying this convention/expectation along with our definition, etiquette indicates that the leaner may continue to lean back. If anything, etiquette dictates that the person seated behind accommodate the leaner peacefully. And that the person behind him do the same. I personally have always found it possible to use my tray, regardless of the recline of the individual in front of me. Sure, there's less space, but trays and seat-backs are very precisely designed to be functional in cramped simultaneous usage. The difference in our opinions, I propose, is not whether etiquette matters. It's whether the impolite person is the one with the knees in the seatback, or the one leaning all the way back!