Also, an extension of our country on another planet would probably be the first move toward humans getting past statism entirely. But that's just a guess/hope.
I prefer that we look at those colonies as societies of their own, not an extension of some country into outer space. Otherwise, the inevitable will happen, and we will have an ugly civil war 200 years into the future. It's better that we look at this as an altruistic enterprise that will eventually yield a shitload of benefit to mankind 200 years down the road.
I think we're certainly capable by now to create a charter that hands the colony over to itself at some point, 10, 20, 50 years in the future.
If he holds to something like this (inflation adjusted), then the availability of a free return will keep your nightmare from happening. Furthermore the free return makes sense from a PR point of view. It is easier to get people to take a risk like that if they believe that they can get back from it. (Though I'm sure at some point there will be interesting litigation around someone who sold their house, didn't bother to pay out the mortgage, then took the money to buy a ticket to Mars, then disappeared to another world...)
So... have a state settle on Mars instead of a company of people mutually coming together will help us get past statism as a species? Brilliant. Truly brilliant.