I had parked a submarine in this narrow channel, when suddenly one of the AIs came with pile of ships, I think it was one galleon and three destoyers or something like that. So the only way through the bay was blocked by submarine, so they attacked it causing a war. I know that the AI knows where every unit is, but I'm wondering if it might be so that they somehow can't see the submarines, since they're submerged, even though they "know" where they are, and that they attacked it by mistake since it happened to be in the way. It didn't seem like they had been preparing for a war. I think a similar thing has happened to me before. So, is it unsafe block sea routes with submarines, if you don't want to have war?