As already stated, there is a certain awkwardness whenever the pronoun "one" becomes the subject of a sentence and, in formal structure, must be retained throughout:
On such a lovely day as this, one thinks of happy times past, when one was doing what one wanted, with one's friends.
A bit exaggerated, yes, but correct. Yet, who talks like this? The example above is most likely to be found in literary writing; a contemporary writer would, generally, avoid such a structure, employing a more reader-friendly format. If you were to use a "person" as subject, your follow through of a pronoun in apposition would be either "he" or "she," which could pose other difficulties for the purist, who would never say "they."
Oh, btw, I believe it was noted as a peculiarity in the ARC commentary that the Society uses the term "lands" in place of "counties": i.e., 'Jehovah's Witnesses are found in over ### lands.'
CC