Save games

Many of the current single-player games (ularn, rogue) let the user save the game state so that they can come back to it later. These save files are stored in the user's home directory. Clever users could use a binary editor to modify the save files to cheat at the game (increasing money, player stats, etc.) to increase their position in the shared scoreboard files. non-clever users could simply backup the save files to restore the game after they die. What strategies could be used to prevent this sort of cheating? Should save files be moved into a shared directory, owned by root.games, so that user's can't edit them? Or is the impact of this cheating so minor that it's not worth worrying about? --Wart