There is a thing about this magical fairy of yours, that most people agree it is a matter of religion and faith, "believe to see" which has nothing to do with scientific knowledge.
Does appealing to the knowledge of the masses makes it an invalid argument if i write it in latin? people here often forgets we are talking about something tangible and physic here, this is not about opinions, I say this because I've seen answers of the kind "people just don't notice". Companies of satelites, gps, airlains, shipping, geologists, astronomers, cartographers, etc, believe the earth is round, and their jobs depend on that. Your answer to that is "they are just mistaken" and who is not? the people on the internet who loves to read conspiracy related material, why do I call you the people of the internet? because this is what you do, you login into a forum to use debate techniques to defend your idea, the real people with real jobs traveling around the real earth, making experiments, investigations, using a round earth model don't seem to notice.
According to your idea, you don't need to know the position or size or proportions of the continents to travel around the world, not only that, you can't even notice if you have it wrong.
So in this case, appealing to general knowledge is a very valid argument.