The whole notion of sovereignty in its current form is an accident of European history. The borders of the world can't be said to be much other than arbitrary, for huge pieces of it.
Seen another way, you could remove the citizenship of people who went negative. Then you'd be rid of your obligations.
If it sounds absurd, that's because it is.
It is not arbitrary. A country has obligations fundamentally only to its citizens. The whole sovereignty thing.