With regard to the Old Course, Matt explained it correctly. That was my principal change to the original routing: Fazio's 18th hole was supposed to start from the 10th green, drive to above the 9th green, then play around the water to a green by the pond. I didn't understand what would stop players from going straight down his 10th fairway [today's 18th] on the bee line from tee to green, cutting 40 yards out of the hole and taking the water more out of play. So, I reversed his 10th and 18th, and broke up the former 18th into two holes to prevent short-cuts.
As for the North Course, there is much less land on the one side of the clubhouse than the other, and I was lucky to find an 8-hole loop that came back to the clubhouse over there. But there was a beautiful site for a par-3, and since none of the founders had a problem with my par-3 9th on the Old course, I figured they wouldn't mind if I did it again.
Players in the Mid-Am can't do it, but when members start on the back nine, they usually play the 9th hole and then decide whether they're going to count it, or play it again at the end