Is there a way I can stop them from this?
I have a populated colony that is actually the homeworld of a hostile race. The fact is, the planet was SO good that the civilians just immediately started traveling to it with colonists (it's Earth-like, 0 colony cost). The world now has about 250k people on it, and each time they bring another colony ship... it's destroyed by defenses. Only after they've dropped off their people, of course. So, it keeps growing, and the companies are losing money.
I could abandon the colony, but that would result in the death of 250k people AND my espionage team.
Ban body gives me an error saying that it can't be used on a populated colony.