Here are some things to ponder:
1. Why would we lie to you, what is there to gain?
2. Why would the government lie to you about a "Ice Wall" and a Flat Earth?
3. If the Earth was flat, I can assure you, we would warn people not to go to the outer edge and there would be strict guidelines, seeing as none of that exists, there is no reason for any Flat Earth guidelines.
Tom, do you suppose it is more expensive to fake raw data and photos, or more expensive to actually send something to Mars (we'll assume that it is possible for discussion's sake). If they were to fake the data, where do the extra billions of dollars go? I'd suspect that it would go directly into the pockets of the conspirators. That is an undeniable potential motive.
Secondarily, I don't assume the government in toto is conspiring, Tom. What need would the government at large need to know about the truth of a round or flat earth?
Tertiary, if you warned people not to go to the edge of the earth, it would be the first thing a damned fool like Steve Fossett would do. Too, people are not exactly lining up to go to "Antarctica" at anyrate. In fact, a BBC film crew reported they were first denied passage there, and then made to feel most unwelcome at a base camp.
I do not assume for a minute, Tom, that you would deliberately mislead us; only that it is possible you are unaware of the conspiracy around you.
Most sincerely,
Ski