[quote=Sauron The Dark Lord]
I would imagine that the Aliens would want the resources, which is the only reason they're on our planet, the only legitimate one, at least. That would keep them from ruining the entire planet in an instant.
[/quote]

Even though the issue is settled, I would just like to ask what resources Earth has that a myriad number of empty planets and asteroids have, and don't require the trouble of expending resources on pest-control?