Karl -
The squared green fronts at Tavistock came about from two separate reasons, the one intended (not sure it would ultimately happen the other a happy accident. We (Forse Design and I am sure others) love restoring the squared approaches to the greens on Classic courses. Mainly because the older greens have haunches, rolls, bumps and such on their front left, center and right corners that were very much a part of the green and its design and strategies. The features were certainly more useful in the old days of bump and run. Tavistocks original greens have plenty of these features. If we were to even slightly round the fronts of the greens we would have missed these great features. They would have been masked under a higher cut of grass. Additionaly, squaring the approaches will allow for hole locations to be cut much closer to the fronts of greens and closer to the aforementioned bumps and such. Typically, courses will not allow the extreme squaring -off of greens because of maintenance in those front left and right corners. Tom Grimac, to his credit, simply said, "we will get it done, just paint the lines they way you want them and they way they appeared in the old photos."
The happy accident came during the process of gassing/regrassing the greens. The sod cut that was made around the green to install a vapor barrier ended up being perfectly straight (especially on holes 11 and 12) revealing a glimpse of what the finished product could be if the green approaches were sqaure. This helped sell the idea.