Playing Siege I had stolen Doom Beams from the Dread Lords. We were in a position such that when two of our ships met the first one to fire would almost always kill the other one and survive without a scratch.
I put together a fleet of five of these ships and noticed that the Dread Lords did not appear to be allowed to use fleets. The problem was they refused to engage my ships, which meant I was free to destroy them ship by ship, since their ships never had the chance to return fire. Their only chance was to engage me first and whittle down my fleet, but they didn't appear to recognise this fact.