We would have thought they were candidates for the loony bin ! LOL
At least you finally admit that your mind can't even begin to process a reality different than the one you "know," because that obviously would mean you would get drug away, sedated and shock therapy'd.
The reality is that the shape of the earth is a globe, or sphere.
There is absolutetly no reality that the earth is a flat disc.
In the unlikely instance of someone in the Navy expressing his (or hers) belief in a flat earth his superior Petty Officer would first take him aside to question him for his belief and then explain to him about the true shape of the earth. If he (or she) had any other mental problems , they would suggest he (or she) get help. The U.S. Navy have excellent facilities and personnel for this. Of course, as far as I have been able to determine, this problem has never occured. You would not get "drug away , sedated and shock therapy'd" unless you became violent. Other than this, I don't think the Navy would take any action unless it interfered with that person's duties.
I was briefly assigned to a position because of my rank and specialty rating in what would be called "Senior or Leading Pettty Officer In Charge Of The Dlvision" . Fortunately , I never had any problems with the ET's in our division. If I had, I think I would have just "handed it off" to the ship's Chaplain rather than get into an argument about the shape of the earth with the person in question. But if you were an ET you would know the earth was a globe from your training in radar systems.
And I had never heard of any persons who even thought the earth was any thing other than a globe until I chanced upon this website, purely by accident.
And I'm just guessing but I think most people except those who work in jobs which depend on the earth being a globe really don't care if the earth is flat or round.