"Completely disagree. I’m not a huge fan of this design either, but it attempts to serve a real purpose that your simplistic moral grandstanding doesn’t acknowledge. If a person takes the whole arm rest without giving their neighbor an opportunity to share, they push against the margins of justice: the areas that are smaller or beyond the scope of legal action and instead played out in societal customs and decorum. As the world democratizes and globalizes we enjoy less and less cultural homogeny in these matters, which leads to either conflict, or one party accepting a perceived injustice in order to keep the peace. If someone wants to pull out a handy divider that makes life fair for all parties and prevents issues, I agree it may not be very elegant, but neither is one party acting selfishly and another being wronged. Common spaces are filled with all sorts of physical dividers and rules that impose fairness, why can’t an individual do the same? Your moral posturing in this article makes it clear that you believe yourself to understand an objective right and wrong, and by writing that this divider signals some kind of breakdown (“we NOW live in a society that...”) you are missing the irony that you are doing exactly what this divider seeks to accomplish. It with plastic and you with online moralizing. At least the divider has some potential hygienic benefits.  "