AI annoyance outposts and colonizations during war

[Buio]

When at war with the AI, the AI often sends colonization ships to do annoynance outposts and colonies far inside your territory.

The UI is poor at telling me when these are incoming so I can stop them. I've managed to stop it sometimes, but mostly due to luck as it is hard taking notice of an enemy colony ship blip in the middle of an intesive war. It's possible there is a good way to find these, then I just don't know where.

Also if I play a "nice" empire, I don't want to kill the colony ships with 30M+ civilians. Is it possible get a "shoot warning shot" option against colony ships so they have to go back home?

During the last game, the Dhayout put up an outpost right inside my home system without me noticing it before the outpost popped up. They sent their own to a -27 system. Presumably for the resource on the planet (which wasn't anything special), but I think the AI did it just to annoy me, and it succeeded.

[Foraven]

That's not a bug per see, you can do the very same if you want to avoid the AI from taking over planets in your territory. You can also invade those planets with ease, they have next to no defences.