@notbatman:
You could more easily make your case for a flat earth by stating that all camera lenses are subject to optical distortion (i.e. pincushion distortion), and could display straight lines as being curved - the same is true for the human eye to some extent.

That being said, the flat earth claims we're under a glass dome of sorts, and that beyond the dome is water. Far fetched, but it does make for fun stories.