I have no deals or treaties with this civilization, yet it seems like the computer is able to fly whatever type of fleet it wants through my territory, and even orbit my systems.
Even if I try to fly a ship into its territory I can't, as we don't have an open border treaty. Actually, if our relationship trend means anything, we are on the brink of war.
In the example below it looks like a couple of scouts, but sometimes Amoeba will fly massive groups of fleets across my territories that could easily wipe me out.
I am green. Yellow is clearly invading my territory.
Why can Amoeba fly through my space, but I can't through theirs?