As someone who used to extensively play factions that could be played passively the whole game without much conflict, I never really noticed this problem. However, I recently took up A few waring races the most recent of which was the Hissho. I enjoyed playing them thouroughly because of their unique "happiness" mechanic however I noticed that at several points while I was trying to invade some major faction star systems, civilian ships would set up a blockade making it unable for my setting up of a blockade on that star-system, while you are still able to invade and to my knowledge civilian ships cannot, if another faction, perhaps one you are allied with decide to come along and orbit the same star (which is being blockaded by a neutral party) you are essentially playing a game of ground invasion chicken with them. (This is the case as when blockaded by a neutral party anyone who is orbiting can invade, who will invade first and will they be successful, or pull the trigger too soon and leave the star-system weak for the other faction. This caused me problems at several points and was very frustrating as my ships would get there first usually, but I would lose the "claim to invade" the system by being unable to blockade as some random civilian ship was in the way.