Every once in a while a rebel fleet will spawn in a puddle of water, completely isolated from ports. As a consequence, there's no way I can destroy it with my own fleets and I don't seem to be able to bribe them with diplomats. The only way to get rid of them is to reload the last turn and just pray they don't respawn.
a) Are there consequences to just leaving them alone? Does the presence of rebel fleets impact order? What about trade (seeing as there's no ports or trade routes to block?
b) If so, is there any way to destroy them? I can't find anything in the console commands that seem to work.