Each player has 48 hours to complete his turn (not counting weekends). After that the Admin may skip his faction or he can be subbed.
Do not bypass or ignore zones of control to lift a siege (or in any other way).
Do not attack ships in ports.
Armies boarding ships in ports can't stay there for more than one turn.
Don't leave blockaded ports without beating the blockading ships first.
Don't stack merchants in armies or forts to get more than one to stand on the same resource (Merchant Fort)
No surrounding armies or agents to destroy them. (Surround&Destroy)
Don't attack units who were left next to a settlement in order to capture it on the same turn in order to cheat the garrison script. In fact don't cheat the garrison script period. (this only applies vs AI factions)
Don't use repeated offers for bribe to increase your faction leader's dread.
Armies that are defeated in battle by a player that comes after them in the turn list may not move the following turn. This is to make it fair for people who are defeated by players that come before them in the turn list, and thus lose all their movement points
Armies that are defeated in battle may not be attacked on the following turn, as they are banned from moving, either by the game mechanics or by the rule above. They must be allowed to move first, or must be reinforced. If the defeated army retreats to a settlement or fort, this rule does not apply.
Ballistas can't open anything, catapults can open wooden walls, trebuchets or better can open anything.
Assassins are allowed to target anyone but the players are limited to one assassination attempt per turn. It must be the first action they do, before they spend money or do anything else. Upon a successful assassination the game admin can load that player's save and attempt the assassination. If the results are different there will be penalties for cheating.
Spies are not allowed to open anything.
ONLY religious buildings can be destroyed upon the conquest of a settlement and ONLY if they are of a religion different than your own.
No trading of provinces to receive free troops. If you trade provinces, make sure they have no garrison prior to the exchange.
No deliberate deals that would put you in debt above -10,000 florins.