First of all, I want to say big thanks to Loulong for his efforts in organizing PBEM community and attracting new players to the games.
There are a few variations of standard PBEM rules for games with human players only or with human players with AI games.
For the human player only games, the
Multi-Site DemoGame rules seems to be the best for current C3C patch 1.22 but they are mostly applicable to 1.15. These rules are very strick and leave almost no loopholes. The complete ruleset can be found at
CDG website
Below is quoted only what is applicable to simple PBEM:
In-Game Glitches/Bugs/Exploits
1.1 - Double-Duty Exploit
Description: No player is permitted to 'allow' the capture of their bombardment or workers with the intent of executing a double-duty exploit.
Definition: Two or more players capturing and recapturing non-combat units (Including bombardment units) with the intent to use them against a third party team simultaneously.
Purpose: To prevent two or more teams from sharing units and their abilities in the same turn for multiple turns.
1.2 - Resource Sharing Exploit
Description: No player is permitted to share a single resource through the use of the Resource Sharing Exploit.
Definition: Two players gifting and regifting a resource as well as cancelling it allow two teams to get use of the same resource that wouldn't be otherwise possible.
Purpose: A resource is to be used by one team per turn, no exceptions.
1.3 - Leader Sacrifices
Description: No player is permitted to barter, gift, or otherwise allow another team to kill-off any of its units with the intent of creating a leader for either team.
Definition: A player creating weak units or sending its out-of-date units after another team with the intent of helping that team create a leader.
Purpose: To prevent great leaders from appearing between two allied players abusing the game system
1.4 - Worker Sacrifices
Description: No player is permitted to barter, gift, or otherwise allow another team to kill-off any of its units using those units with the capture ability with the intent of creating a worker for either team.
Definition: A player creating weak units or sending its out-of-date units after another team with the intent of helping that team create workers.
Purpose: To prevent workers from appearing between two allied players abusing the game system.
1.5 - War Happiness
Description: No player is permitted to declare war on anyone with the intent of generating some happiness amongst its populace.
Definition: A player declaring war on another just to invoke a little extra happiness.
Purpose: To prevent this 'feature' from being exploited and retain the spirit of the game.
1.6 - Invalid Map Trading
Description: No player is permitted to barter, gift, or otherwise trade any sort of map, whether it be a screen shot, minimap, hand drawing, or any other 'picture' of the in-game map, mini-map, or embassy screenshot before the requisite tech is discovered. Verbal/text descriptions are allowed, but coordinates are not.
Definition: A player creating screen shots, drawings, or other depictions of any part of the in-game map before the requisite tech has been discovered.
Purpose: To prevent the use of outside game elements to break the spirit of the game by allowing maps to be traded before they are allowed in-game.
1.7 - Exchange of Contact
Description: No player is permitted to barter, gift, or otherwise trade any sort of contact information until the requisite tech is discovered. A simple statement to team 'Z' that you live next to team 'Y' is allowable so long as no transactions are made or brokered between the two.
Definition: A player trading anything for any location or contact information before allowed in-game.
Purpose: To prevent the use of outside game elements to break the spirit of the game by allowing contact and location information to be traded before they are allowed in-game.
1.8 Enjoining Teams
Description: No player is permitted to barter, gift, or otherwise trade multiple cities with the intent of joining player to destroy another player and keep both players alive to survive to the end.
Definition: A player trading one or more cities to another player for the purpose of either granting that player an advantage (premature contact with another civ, map information, etc.), or denying an aggressor the right of conquest.
Trading and or gifiting cities is permitted, but each transaction shall be reviewed by the administrators of the game. If a specific transaction is considered to be in violation of the spirit of this law, then the traded/gifted cities may be forcibly returned to their original owner(s) or simply abandoned at the sole discretion of the administrators.
As a general rule, the administrators will consider city gifts/trades that are temporary in nature (ie. only a few turns in duration) and those given/traded for the purpose of granting a player an advantage (premature contact, map information, etc.) or to deny another player the right of conquest to be against the spirit of this law.
Purpose: To prevent the use of outside game elements to break the spirit of the game by allowing contact and location information to be traded before they are allowed in-game or to unfairly prevent a conquering civ from taking your cities.
1.9 - Improper Use of Military Great Leaders
Description: No player may use a Military Great Leader to rush a Great Wonder. (not applicable to C3C)
Purpose: To prevent Military Great Leaders from being used in a manner inconsistent with their original purpose at the beginning of the game.
Metagame Tricks
2.1 - Reloading
Description: No player is allowed to reload the game with the intent of altering the outcome of any event, combat, or other in-game result.
Definition: Someone reloading the game when something happens that they don't like and wish to change. Playing the turn in a different order to alter the outcome of said happenings.
Purpose: To prevent a player from replaying a turn until the most optimum outcome is achieved or otherwise increasing their odds of winning.
2.2 - Save Manipulation
Description: No player is permitted to use the PBEM savegames or other files to obtain information or alter any in-game element. This includes monitoring or altering memory while the game is loaded. Using MapStat is also prohibbited.
Definition: An individual scanning or monitoring loaded files into memory or altering a file can obtain location information and more, they can even alter in game data.
Purpose: To prevent the use of outside game elements to break the spirit of the game by allowing someone to outright cheat.
2.3 - Zoomed Loading
Description: No player is permitted to have their settings set to have the game zoomed out when loading a PBEM savegame.
Definition: Loading the game when zoomed out can reveal information that you would not otherwise have access to.
Purpose: To prevent the gathering of information against the spirit of the game.
2.4 - Misleading through Renaming
Description: No player is permitted to rename a unit or city with the intent of misleading or confusing opponents.
Definition: Cities can be renamed to names of tech or sums of gold or anything else in an effort to not trade what that opponent agreed to. Units can be renamed to other units and appear to be something else entirely.
Purpose: To prevent the misleading or confusion of another player through malicious use of in-game features.
Game Mechanics tricks
3.1 - Fortifying a boat/passenger
Description: Similar to 3.1, except now addressing sea vessels. The sea vessel also would enjoy increased visibility during the next turn. A player can move the vessels the full allotment of movement points then wake the passengers and give them then Fortify all command which fortifies the sea vessel as well. It is allowed to use the Fortify All command on a vessel or a stack of vessels that has movement points left before the command was issued.
Definition: A player may get the effect of a sea vessel being fortified prior to an attack when that vessel should have not have been able to fortify itself because it had no movement points to do so.
Purpose: To prevent the illegal use of having increased visibility.
3.2 - Hitting F1/back-forward to change production
Description: It is possible to use F1 to go into city views and change production or rush items before a city has been reached in the pre-turn production queue.
Definition: This can result in tech-enabled units and Wonders being completed the very turn the tech is researched, or production to be changed in response to an enemy's actions (like Walls if a stack moves toward a specific city and not another).
Purpose: To prevent the unfair allocation of resources not intended to be used in a certain way on the previous turn and keep gameplay flowing within the spirit of the game.
3.3 - Hitting F1/back-forward for double tile usage
Description: It is possible to use F1 to go into city views and use the Forward/Back buttons to change the work force allocations before a city has been reached in the pre-turn production queue so that a tile can be used to used by 2 or more different cities in the same turn. .
Definition: This can result in the possibility of a bonus tile being shared by 2 or more cities.
Purpose: To prevent the unfair allocation of resources.
3.4 - Using GoTo/Auto-Explore/Auto-Workers to get extra movement
Description: The last team in the turn order can issue the GoTo command, and have a unit move twice before the next turn begins. This is very strong in war-time. Every Civ has that option, that's why it is stipulated that no one use go-to. Note: This does not provide an extra turn of movement, but rather advances the timing of that movement (ie. 2 moves in turn 1, and 0 moves in the final turn of the task). Similar results can be achieved with auto-explore and auto-workers.
Definition: This can result in the last player to play in a given turn, the ability to move their units twice before another player could move in between
Exception: Automation of worker tasks (roading, mining, irrigating, etc.) is permitted. Stack & individual unit movement that concludes within territory currently (when order is given, not when units arrive) visible (ie. not unexplored and not in the fog of war) is permitted. Automated moves are subject to administrator oversight. Contested moves that result in an unfair advantage (ie. arriving at a location before another team that would have arrived first, but wasn't using automated movement; reinforcing a poorly defended city or location; etc.) will remain a violation of this rule.
3.5 - Chaining naval transports to quickly move land units across water
Description: It is possible to wake a land unit at sea, and transfer it from one transport to another. Given enough ships, a chain can be created to instantaneously move units across bodies of water (by ending in port).
Verdict: This is to be allowed.
3.6 - Teleporting units gifting cities
Description: A player can instantaneously transport units from any city back to their capital by simply gifting it to another player. This results in very weird strategy.
Definition: This can result in a Civs units being transported out of harms way or to a new war front.
Purpose: To prevent the unfair movement of units; especially during war time.
3.7 Accepting a Peace Treaty from a Civ then immediately declaring war
Description: A player at war with another can accept the latter's Peace Treaty, then declare war afterward in order to eliminate War Weariness from that player. This results in a huge advantage if the peace-seeking player is not aware of the trick.
Definition: This can result in a players properly acquired War Weariness being shut off and the possibility for the other player to suffer from it should they redeclare war.
Purpose: To prevent unfairly using the games mechanics to negate or reverse the effects of War Weariness,
3.8 - Staying at war to upkeep War Weariness but not actual fighting
Description: Being kept at war by a player with the intent of inflicting War Weariness, and the penalties that are associated with it.
Definition: This can result in a players War Weariness being applied and worsened when the team no longer wishes or is able to wage war against the other.
Purpose: To prevent unfairly using the games mechanics to increase, exaggerate, or prolong the effects of War Weariness when waging war is not a reasonable option as determined by the game staff.
Reputation and Honor System
4.1 - Official Treaties
All in-game treaties can be submitted to the game admin for an official record. All players in the treaty must confirm the exact wording with the game admin for the treaty to be officially recorded.
4.2 - Distribution of Treaties
All offial treaties will kept private. The only exception to this is where a player in a treaty asks the game admin to send a copy of the treaty to another player.
4.3 - Fairness Pledge
Every player must agree to the fairness pledge before the game starts:
I pledge to compete fairly and within the rules of the game. I pledge to adhere not only to the written rules, but also to the unwritten, spirit of the rules. I understand that failure to live up to this pledge may result in penalties for me.
4.4 - Battle Log
Description: For all combats, players must submit a log of what units attacked, retreated, died, won, etc. from each battle on that turn to the team they attacked. This includes the capture of units and cities.
Ammendments
5.1 - Addition of Newly Discovered Exploits
5.1.1 - Authority
The players agree to abide by the rulings of the game admin should a new, previously unknown bug/exploit appear in the game.
5.1.2 - Disclosure Requirements
Every player has to control its own actions and to look for bugs or game mechanics which could be defined as a bug or exploit. When a player finds such a mechanism (which may or may not known by other players), they are compelled to bring this to the attention of the game admin immediately.
The game admin will be responsible for resolving the issue amongst the concerned parties, or in the case of a potential new exploit, the admins will be responsible for facilitating a discussion (while preserving the anonymity of the identifying player) and a vote on the issue.
...
Enforcing these rules is very easy once you have the admin password to the game. Just check the thread at CDZ 
). Indeed this is only to keep all players informed in the thread (as tracking) while the save is sent by e-mail. 
