George:
Gil Hanse was very involved in the original course at Stonewall ... he was the primary shaper and made numerous suggestions on contouring greens, bunker placement, etc. He received co-design credit for the course, though he did essentially the same things that my other associates do on our current projects. Stonewall was the last project Gil worked on with me before moving to Philadelphia to try his own thing.
The hole on the new course you referred to is the 15th, which runs along the boundary with the third hole of the Old course. There are three tees for #15. One tee is ten feet off the right side of #14 green, which they use a lot, but is not so good for busy days and the tee is quite small. Another tee is down across the stream, which makes the hole very difficult [you have to hit a draw to get to the left side of the fairway], but they weren't allowed to build a bridge to it when we were working on the course, so we needed an alternative to spread out the wear and tear.
That prompted us to build the tee you noticed, up to the left of #14 green above the approach bunker. 15 is a great looking hole from that angle, and as long as there is not another group right on your behind, you can go up there and tee off before the group behind starts walking across your line to 14 green. That is the sort of feature I saw a lot of in the UK and Ireland when I lived there, and which I will pull out of the bag of tricks sometimes when we are building a private club with limited traffic such as Stonewall. I don't know whether they ever put tee markers on that tee or not, but I've played from it a couple of times and thought it was terrific. I've still never played the tee across the stream.