Bossbird - because the 1st round lasts for 3 days, it can be very easy to forget to play the 2nd round if the 1st round was played on day 1 of 3. But as you say, that is quite a large number; I think I've seen maybe half a dozen players at most.
BlackBogey - the 2nd round definitely lasted 2 days for me, are you sure you didn't play your first nine holes on the 2nd day of 2 by mistake?