Actually, it's a set of basic questions.
Claim: The Earth being round is apparently faked by a bunch of conspirators.
Problems; lots, but two very fundamental ones:
1. When and how did the conspiracy start?
2. How did the conspirators figure out the "true" shape of the Earth? Why are they the only ones that figure it out? Why didn't Galieo, Newton, Einstein, etc. figure it out?
Answers:
1. It didn't. In order for the conspiracy to have covered up the numerous examples of circumnavigating the globe, it would have to predate the NASA space program, thus meaning that there would be no motive.
2. They didn't. The conspirators would have no logical way of knowing the shape of the Earth to any greater extent than today's scientists do.
Possible rebuttals:
1. They could have been preparing for the NASA space program!
-Implausible, as there would not be any motive for those people to prepare some grand scheme so that future generations can scam people of money, not to mention that they could not have known that the NASA space program could have started, as it started due to many circumstances beyond their control.
2. They could have thought that the Earth was round before but then changed their minds upon viewing satellite photos, and quickly devised a conspiracy to cover it up.
-Implausible, the time needed to devise of such a conspiracy would take far, far, far too long to devise on the spot.
Alternative rebuttal for number 2. They could have figured it out using the same methods that this forum uses.
-Laughable that some random conspirators would be more knowledgeable than the combined consensus of today's Scientists.
Conclusion: If the Earth were flat, the conspirators would not have any way of knowing that that Scientists for some reason wouldn't also know from. Unless if aliens came and told them, or some angel came and told them, they would have absolutely no more clue about the shape of the Earth than today's scientists, who know for a fact that the Earth is round, especially from satellite images from space. Therefore, the conspiracy is clearly bogus, and therefore the Earth is round.