At the request of FAL I suggest the following rules (most of them are R*oken69's).
It is forbidden to
1. Attack with pirates as well as comparatively very small fleets, only made to inhibit loading/landing
2. Release a vassals during wartime to hinder an enemy
3. Turbo-Burn manufactories, i.e. repeated go and stop orders to an army
4. DOW with the aim of increasing stab of the DOWed nation
5. Exploiting Simultaneity: Any public agreement between players that would occur simultaneously in the real world but that, due to limitations in the game engine cannot be done simultaneously, must be adhered to. This rule includes, but is not limited to, any type of "sale".
6. A Counter-Reform Catholic nation cannot declare war on a catholic nation that has all catholic player allies. You may not go back to normal Catholicism until the edict of Tolerance.
7. No map trading with the AI
8. A player which is force-vassalized must remain a vassal for at least 20 years. Forced and Diplomatic Vassals are required to submit to any request by their overlord that is not self-destructive (GM interpretes). After that a vassal wishing to disobey his overlord must immediately cancel vassalization.
And of course, in case there is doubt how to apply a rule in a specific case the GM is the arbiter.
PS Good thing Fredrik and Ozzeh are not in this game. They would have great trouble remembering all of this