I mean, really? Who would care to hide something like that? I don't buy the hiding God theory that many espouse. It doesn't make sense.
That's the rub, isn't it? "Why?" All these arguments about science needing to save face, bowing to social norms and pressures and the like I might be able to buy for the short term, but not for the generations and generations we're talking about here. If for no other reason than there's no money in it, no real money, anyway. The only reason to stage such a huge cover-up, the only way to motivate the large and diverse number of people necessary to pull such a thing off in this day and age, is greed or fear. If there's a massive RE hoax being staged by every government on earth, it's because they've discovered what's on the other side of the "Ice Wall", and they've decided that it's so wonderful/dangerous that only a select few should have access to it. Which is ridiculous. Seriously. We're talking about the human race here. Some nation would have tried to claim it by now, in bloody battle most likely, either to have the wonderfulness all to themselves or to weaponize the horror.
There are a few, simple ways to verify the accuracy of the RE model over FE that can be done with simple observation. One of the easiest, real-world examples has to do with distances. The flat projection of the FE world causes huge distortions in distances between given points when compared to what can be observed and measured in the real world. The RE model puts the diameter of earth at 7926 miles at the equator. The FE model puts the diameter of "the known world" at 28,769 miles. This would result in a FE diameter at the equator (if you place the equator midway through the known world, an assumption on my part) of 14,384 miles, which is nearly double that of which has been directly observed and measured. The further south you travel, the larger the distances become. So what should be a 4265-ish mile (observed) trip between Buenos Aires and Cape Town suddenly becomes an epic 10,304 mile journey!
I welcome all corrections to any erroneous assumptions or calculations I have made.