Actual rules vary between games since there are sometimes different interpretations on how to handle game bugs. Reloads are always a no-no though.
Here is what Tau Ceti provides upon joining the Apolyton tournament
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If you are new to this tournament, please read our rules here:
http://apolyton.net/forums/Forum27/HTML/000245.html
If you are new to PBEM in general, a quick overview of the procedure
can be found here:
http://apolyton.net/forums/Forum27/HTML/000356.html
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These are just an example and there are lots of players who play differently. You will note that some of the rules involve the quirks of Multiplayer diplomacy but and some known bugs in the game. Essentially it is not a "cheat" as long as all players are aware of the ruling on the feature of the game. Actually if you look at most of the "non-tournaent" games in the Multiplayer part of the Forum you will usually see discussions on the rules to be used.
If you are uncertain of a certain behavior it is usually easy enough to ask in this forum. Etiquette usually requires that you notify others if you cannot play for an extended period (48 hours or more). AS for rudeness-- its simple-- don't be rude. If in doubt err on the side of politeness. The AC part of the board has seemed to be incredibly civil. There is some in-game and in-character trash talk between warring factions in the MP threads but its all part of a bit of role-playing. The more heated discussions and rudeness are usually over in "Off-Topic" but that forum is actually relatively polite as well. The mods will not tolerate BS.
Actually my advice would be to take a look at the threads in the multiplayer section and scan through them. A quick look would indicate a lot about the tone and the rules requirements. Then to start
1.just chime in on some game that is starting there
2. Find and post to the tournament set-up thread
3 Or Post your message to start your own game on your preferred settings and with your preferred rules
Best of luck and have fun with it.