Tom,
That's a very good point. We don't know what the motivation was to bring Alison in to review the plans. In Alison's 6 1/2 page report, dated May 15, 1929 he characterized the general land for the golf course (at this stage it was expected to be three nines); the framework for the design, "The framework actually proposed does not require much general comment. The total length is adequate; the distribution of length is excellent; changes of direction are frequent; natural features are admirably used, and those not used are reduced to a bed-rock minimum." Alison wrote a hole by hole detail review; a discussion about Flynn's unique planting plan, "On the low land it is the intention to place high growth on the higher portions, and low growth on the lower portions, and to produce in this manner an illusion that the ground is undulating." Finally, Alison concludes "...We have said that some of the land is lacking in natural feature...It is natural that we should have looked ot see whether we could avoid in any manner this comparatively mediocre land. But we must not lose sight of the fact that there are few courses which have so little featureless land. If a coldly critical eye is turned upon some classic courses, it will be observed that they have several holes which owe much to Art and little to Nature. We may also remember that the beauty of the scenery is an enormous asset in your case. With this to your advantage you can easily afford a few artificial holes.
We may also consider that the greater part of the land is of exceptional merit.
We are entirely satisfied that Mr. Flynn's plans are as good as can be made on this site and the proposed course will prove to e of the first order."
Pretty good praise from Alison, whom Flynn declined to go into business with 6 years earlier. Interestingly, Flynn's solution to the flatter land was to create undulating sandy waste to introduce strategy and aesthetic qualities where it was lacking. He did so in a way that tied in beautifully to the surrounds creating a harmony of design. Where the land had more topographic movement, he relied on natural features to dictate strategy. In areas that required more engineering (such as the 9th green and the removal of the ridge fronting the 14th green) he was able to hide the architecture and make it look natural. Flynn's planting plan, though not used (probably because of the expense and the onset of the Depression) was brilliant.
But why was Alison brought in? Was he more famous than Flynn? Except for a small 9-hole course west of the Tappan Zee, Flynn did not have any projects in NY at the time. Juan Trippe recommended Flynn to Lucien Tyng. Perhaps Trippe knew of Flynn based on Flynn's work for Glenn Curtiss and his other Florida projects, particularly Boca Raton in addition to Atlantic City CC, Cascades, Pine Valley, The Country Club, etc.
I doubt Macdonald or Banks were brought in to compete for the Shinnecock job. Macdonald stole their flag and chef and Banks was a close follower. Flynn's use of the natural ground as much as possible and his architecture based on naturalism (he was the Nature Faker) appealed to the Club. His attention to costs and accurate estimates was also something these businessmen appreciated and responded to.