Somehow, I knew a "pale" was a post and that the phrase made sense as being about going beyond a boundary. I have NO idea why I knew "pale" was a post. Possibly because the extremely broadest of accents I had to deal with as a child would have pronounced "pole" as "pale"? (They certainly pronounced "door" as "dare". Not sure if it's Glaswegian or Ayrshire - East Kilbride spoke some random bastard breed of the two.).