I’ve long been fascinated by what I call “normative density”–the quantity of normative claims made within a given public space. Public transit is a common location for high normative density. The picture* above–taken in a subway in Philadelphia–is a good example. In addition to the standard warning signs about how and when to exit the subway car safely, there’s also a interesting sign cajoling riders into using up only their fair share of space. Note that “Dude it’s rude” is, from a normative point of view, in a very different space from signs that simply forbid the relevant behaviour.
*Apologies to the friend who sent this photo to me–I’ve lost track of who you are! But thank you!