Here's a follow up image that describe what I'm talking about. Mormegil was a Torian colony I attacked and conquered. My civilization for the most part is on the other size of a gigantic sized galaxy, and I have 3 pure attack ships (read:they'd die if attacked) guarding the planet I just conquered. There's no way I could send any support for atleast 10 turns. The problem is, the Torians have several massive fleets just randomly stacked all over. They will not use these and I can run transports right by them. This is on 'suicidial' difficulty, btw, so the AI isn't just being 'dumb'. =/
And here's a pic zoomed in on one of these stacks. Look how many stacks there are:(