So long ago I played this system with the inventor, Bob Sundby. While the 3-card major response came up occasionally, alerting it always had opponents watching out for what Bob would call a "rara avis."
That was exactly my reasoning. With a fifth diamond, would have bid the grand last time. Some feel that even what you hold is enough, but it is possible that he has a stiff club. We know he has a second round control.
Perhaps because of common perceptions about our game (tea and crumpets)most of us appreciate that notable people share our interest. Gen. Eisenhower, Omar Sharif, and Justice Byron White are a few examples. Long ago, Sports Illustrated carried a bridge column. Here (link below) is Charles Goren's account of ...
TBW used to have a section listing the top panelist scores, but they dropped it for the reasons you mention.
How about getting some regular partners and teammates to join you in answering. You can play the contest with your official answer, and stimulate discussion with the privately-circulated option 2.
I know that the NT rebid is the agreed method in our partnership. Many of my partners prefer this. My sense is that we have been going against the prevailing style, and I was curious.
Thanks to you and other who took the time to vote and/or comment.