I think multiple reloading of the turn IS cheating especially in early part of game when looking for ruins. Its impossible to detect and so must rely on individual gamer moral.

How about the ability for a game host to eject a player. For example a new player joins a game, playes 1 or 2 moves and never plays again. The player will eventually become removed if he is skipped but this can lose the game 4 days play if set to a skip level of 4. Give the host the option to remove the player if its obvious a game is being disrupted in this way.

I like the the player turn scheduling idea suggested by Tanuvein and Tazzik.