No, but rules of a game must be either prestrictive or restrictive. Restrictive rules tell you what you can't do, and prestrictive rules tell you what you can do. For example, in sports, it is impossible to completely define what a player can do, so we tell players what they can't do (in soccer/football, to describe everything that players could do, we would have to describe running, walking, kicking, heading, etc. to a high degree of precision, and referees would have to carefully watch that players did nothing else. Instead, it is much easier to make rules defining what players can't do [let the ball touch their hands or arms, foul other players in specific ways, pass to an offsides player, etc.]) However, in a board game, it is much easier to describe what CAN be done. The rules tell you how moves are inputted, and what results based on that. They don't described completely what PLAYERS can do, because that is not important - they describe what happens to the pieces on the board under what circumstances. If we interpret diplomacy rules as prescriptive, the game works the way we intend it to (basically the way it works on this site). If we interpret the rules as restrictive, all chaos breaks loose. Not only can we move pieces while no one else is looking, we can move pieces while everyone is looking, then punch them in the face when they complain and/or try to move them back. Because the rules don't mention that a fleet is allowed to be replace by a submarine that moves only on sea spaces, but moves two spaces a turn, I think I'm going to do that. This way lies madness. The only way to interpret the rules of Diplomacy that makes a game worth playing is if we assume that the rules describe what CAN happen, not what CAN'T. When I said the rules "completely define what is allowed to happen on the board" this is what I meant. I did not mean that they create a perfectly complete and logical system. The convoy paradoxes are a flaw in the game, not an invitation to cheat in whatever way you want.