The name and the idea are only of historical interest today.
11 November 1938, New York Times, pg. 28:
PUT ON NEW PLANE
Covered Gallery is Provided at
Rockefeller Center for the
WATCHERS RECEIVE CARDS
All Due to Interest of John
D. Rockefeller Jr., Who Has
Been Chased Away Himself
Because John D. Rockefeller Jr. is an "excavation fan," those men, women and children who like to stop and watch while others toil at new construction work won an important concession yesterday. The first "excavatiing watchers' club" was dedicated at Rockefeller Center. Any any one who wishes to "take in the show" as workers dig and drill and blast for a new unit of the Center, from now on may stand and watch in comfort.
It was estimated that about 1,000 persons exercised the privileges of the club during the first day of its existence.
12 November 1938, Washington Post, pg. X3:
Steamshovel Kibitzers Get a Break
Dreams of those who like to stand and gaze at building foundations in the process of excavation came true at New York with the formal dedication of the Sidewalk Superintendent's Club at the site of the new 16-story building in Rockefeller Center.
12 November 1938, Christian Science Monitor, pg. 3:
NEW YORK (AP) - John D. ROckefeller, an old steam-shovel watcher himself, has made Rockefeller Center safe and comfortable for curbstone kibitzers around excavation projects.
Getting the idea when a business-like foreman gave a spectator the heave-ho - "sorry, Buddy, you gotta move on" - the present steward of the oil-made millions established the canopied "sidewalk superintendent's club" on the site of Holland House, the newest building planned for the midtown group.
14 November 1938, Christian Science Monitor, , pg. 5:
"Sidewalk Superintendents" Organize
Exalted Order Of
20 March 2005, New York TImes, city section, FYI, pg. 2:
Legend has it that Mr. Rockefeller, who loved to watch the construction of the complex that bore his name, once stopped at the entrance to a trucking ramp, only to be told: "Keep moving, buddy. You can't stand here all day."
His response, in November 1938, was the Sidewalk Superintendents' Club, a wooden shed on Rockefeller Plaza between 48th and 49th Streets, complete with free membership cards.
The trucking ramp story has a nice egalitarian ring to it, but it was just a legend, according to Daniel Okrent in "Great Fortune: The Epic of Rockefeller Center" (Viking, 2003). He wrote that the idea apparently came from a platform for kibitzers in Des Moines and was apparently picked up by Nelson A. Rockefeller, Junior's son.