[sir_pudding]

It really depends on where in the world they end up. In some places "warlord" is a profession just like where they came from and "whose militia are you in" is a more important question than "what is your citizenship". In other places they probably will be swept up and put into a prison camp. In most industrialized countries they likely will be ignored until they do something to attract attention. It isn't like there are large international databases of biometric data, where every person is accounted for, and they have to routinely pass checkpoints (unless the setting has has this specifically).