They can do pretty much what they want unless there is a political movement in multiple countries to stop it. In other words, there has to be profit for a bunch

They can do pretty much what they want unless there is a political movement in multiple countries to stop it. In other words, there has to be profit for a bunch politicians to stop it or what they're doing has to be highly morally unpalatable. Given there is no apparent profit for Elon Musk in going to Mars in the first place, it's unlikely a bunch of politicians will find profit in stopping him. There's probably votes in smoothing things over for him because hope always wins more votes than negativity.