Yeah, and people would come up with ways of attacking through the communications networks -- so war would look very different, but it would exist. (Or would it? If you can find someone to build them for you, you can control drones via communication. So you might just have robot soldiers constructed on world instead of sending your own people.)

Hahaha, probably it happens at least once. (And there's no way to force people to comply with your local law, because of course extradition is impossible...)