1- What are the colonists' fundamental rights and who protects them?
2- Under what jurisdiction will they be?
3- Who owns the air?
4- If someone can't pay for their air or food, what happens?
https://en.wikipedia.org/wiki/Space_law (covers at least 3) https://en.wikipedia.org/wiki/Human_rights_in_cyberspace (covers at least 1)
Has SpaceX even had a successful manned space flight yet? I don't think we're quite on the "verge" of colonizing space...
We better start thinking about the legal issues now, as they are complicated, rather than just doing it in a rush when it starts happening.
That flight will likely happen in the next quarter.
Meanwhile, while SpaceX has been wading through NASA design reviews and red tape (some of which is probably good for them!) for Falcon 9 + Crew Dragon, they've been hard at work on this next-gen rocket for years (the engines since 2009, the rocket itself since 2014). We will likely see a SpaceX Starship reach Low-Earth Orbit within a year, so it's time to start considering what other requirements for getting to Mars might take longer to build.
The rush to get people into space and men on the moon was because of politics. If Musk wants people on Mars, he doesn't need bodies in orbit, he needs ships capable of carrying bodies in orbit. It's fine (and unnecessary) if they're unmanned. Which SpaceX has already done, docking with the ISS. NASA and the USSR were hasty putting people into orbit because it was a political necessity, not because it was important to the goal of developing ICBMs, surveillance satellites, or whatever else. They each needed to be the first to put an object in orbit, a human in orbit, a human on the moon, etc. Musk needed cheap, reusable spaceflight as an intermediate goal and a maned Martian capable profile as goal number 2. He doesn't need to take his picture at all the road signs along the way.
Musk at some point said he wanted to launch a human toward Mars by the 2024 launch window. I think this is optimistic, but it's not that far off. I would be surprised if they don't launch in time for the 2029-ish launch window.