Jeremy, if your intention is to give credence to this theory that Earth is flat, definitely do not ask them to explain ships at sea sailing over the horizon, the only existing magnetic monopole in the universe (our North Pole, in their theory, is a scientifically impossible one-of-a-kind), or the magic, carefully guarded secret ice wall surrounding the entire edge of the only flat planet in this quandrant of space.
Their answers, if you are prepared with the right questions, will only make them look like fools or like people attempting to make you look like one for taking them seriously.
If your piece is intended to show that Western civilization also has blind followers of ridiculous religions, carry on; you'll succeed wildly.