My guess is that you'd do it from the Moon with some plausible deniability.

Couldn't shoot up everything leaving Earth orbit, couldn't shoot up everything which decided to orbit the Moon. Would be illegal as all hell, and take way, way too many resources. And invite retaliation.

Might be able to do something to a very fragile lander either just before or just after landing.

Would never have to be known as an attack. Communications could just fail. (Maybe there is an ETI colony on Mars which got tired of visitors, decided to take out the last two. Kidding. Just kidding!)

A companion orbiter might be keeping track, couldn't do it all the time. Two could, and one of them might have to suffer a communication problem, too.

Another interesting issue, one for the lawyers, is the guys idea of private ownership of land. I think land ownership flows from nations, and is dependent upon whatever way that country decides to handle it. Measurement, ownership and transfer is a big deal.

LaSalle, Cortez, and so on, did not claim ownership for themselves, they did it in the name of a country.

With no national ownership, I wonder how a private entity could own land.

I think when an invader takes over, unless they recognize the previous property ownership, all bets are off. Without a government and body of laws to protect rights, they are worthless.

An analogy might be the sea bottom outside the 12 mile limits. Fish, wrecks, and minerals generally go to whoever avails themselves of them. The land under the water cannot be owned by anyone.

It can be claimed, but not owned.

As always, if you can take it and protect it, it's yours. Look at the Israeli settlements in the West Bank and Gaza. No government is strong enough to drive them out, so it's theirs.

That does, though, invite legitimate retaliation everywhere in the world, except the Middle East. There retaliation is regarded as somehow not right.

Arf