There's nothing wrong with saving the game and reloading later. I certainly don't have two or three hours of uninterrupted time to complete a turn in a CG very often. AFAIK, the server doesn't have any way to tell the difference between you saving at 1200 and going out for lunch, resuming your game at 1400 and you saving at 1200, restarting, playing for two hours, not liking the results you got, quitting without saving, and reloading from your old save to try a different approach. Not doing the latter is called playing fair.
If I do have some unanticipated interruption in play - power goes out, for example, or I get up and walk away from my laptop and the battery dies (happened a few weeks ago) - that causes me to have to repeat some portion of a turn that I had already played, I always inform my opponent. And I try, as best I can remember, to repeat the moves I already made.
Ultimately, fair play comes down to trusting your opponent. If you suspect someone is cheating (winning every single battle at odds of 2.01 to 1, for example), you just concede the game and don't play that person any more.