PDNWOTGIYAGA

Smith College's way of saying "please do not walk on the grass if you are going across." Specifically, it is intended to keep students from walking through Chapin Lawn towards Wright Hall or Neilson Library, rather than going on the paths around the lawn.
It is also kind of an inside joke, as only students who attended orientation understand the acronym and visitors are puzzled by the long, seemingly-meaningless word.