What bothers ME about this thread is to see Tom Bishop attacked like this.
He is answering questions as patiently as he can - seems like he carries the weight of this site almost alone, when it comes to the "roundies"'s questions.
Fact is, navigating Antarctica is almost impossible to "test", it's all ice, even if someone DID come back saying that they went all around it once and it took forever, PROVING flat earth - it would be easy for a round earth person to just say "you went around it several times, you were confused".
The opposite works too. One could say, "You didn't prove a round earth - you just went down and looked around and turned back".
The idea of the direction of "what is south" is very confusing in the flat earth model. Because we are taught (wrongly) that the earth is round and that Antarctica is a small pile of ice at the south pole, when in reality Antarctica surrounds the rest of the world, and the fact that antarctica is just ice - makes it very hard to understand (in a round earthers mind) just what they are doing when they go there.
You cannot go to the "other side" of the ice, but you THINK you are doing that. And at any point you turn back, you are headed north - just like in the "round earth" model! It's very hard to argue and win - no matter what side you are on - the "evidence" seems to support your belief, no matter which you believe!
So, after all of this, I am content, here we are, on a solid, still earth that we don't have to fly with, like so many ants - crawling around a balloon.