Is there any possibility we might get a little notification pop up? Something along the lines of "Urist Mcplanet is under attack from a Hybrid Hive!"
Maybe a popup that says "SIEGE!" 
Yea, I'm planning on adding warnings when they're actually on your planets, just been thinkering about a more scalable system of handling these kinds of "ongoing events the player has intel on and should be told about" because honestly there's going to be a fairly large number of them when all's said and done.
I proposed a watch post similar to a guard post, freely available and cheap. You could build one on any of your planets and whenever there is a hostile on that planet it will place a warning message on your screen.
For extra points you could make them customizable so we could set a custom warning message for the to display, and a threshold required to set them off (IE, only warn when there are 10 or more enemies on this planet), and other such things.
(Edit by Keith: crap, sorry, I hit modify instead of reply... again. This was my reply:
I proposed a watch post similar to a guard post, freely available and cheap. You could build one on any of your planets and whenever there is a hostile on that planet it will place a warning message on your screen.
That would be helpful for direct attacks in human territory, but I'm having to come up with an intel-aggregation scheme for stuff happening on hostile worlds where the player has scouting, too, and not always related to numbers or strength of enemies present.
)
