I found this forum because I made a search that found this specific thread. It looked very promising:

---'How, do you think, is the "round earth" conspiracy working? How is it kept a secret? How does the conspiracy hire new people? How many people 'know' the 'truth'? Why hasn't it leaked yet?'

It is an immensely important question, but it has denigrated into yet another detailed question about trig and engineering, eg:

Quote from: stack on August 09, 2019, 07:12:25 AM

[Geodetic

I am unaware that plane survey finds no curve. Citation requested. There's plenty in Geodetic Surveying that suggests otherwise.

Geodetic survey is nothing but the application of spherical trig to plane survey , so enables earth to be mapped on to sphere .

"Geodetic survey considers the earth as a sphere . Planes survey considers  earth as a plane - the approximation being within the permissible error for areas up to about 100 square miles. The former involves knowledge of spherical trigonometry ."

From the introduction in the book " Elementary surveying " by Arthur Lovat D.Sc , A.R.C.S., A.M.Inst.C.E.
University reader in Civil Engineering at the University of London published in 1946. Page 1.

https://en.wikipedia.org/wiki/Surveying#Plane_and_geodetic_surveying
You can see that even Wiki acknowledges this 100 mile square area in which earth is mapped as a plane.
The fact is , if trigonometric survey - which requires no assumption of shape of the area under scrutiny - finds no curve over 10 miles ,  then there is none unless it is so small that it cannot be accounted for within instrument error .

Can I ask if this be brought back to the original and proper subject?, that is:

How, do you think, is the "round earth" conspiracy working? How is it kept a secret? How does the conspiracy hire new people? How many people 'know' the 'truth'? Why hasn't it leaked yet?'