They won't if you don't make it worth their while by sharing of your resources. There's many an apocalyptic novel which contains just that scenario where some r

They won't if you don't make it worth their while by sharing of your resources. There's many an apocalyptic novel which contains just that scenario where some rich person created himself a hideout stuffed with tech and food and weapons (and more weapons, and even more of them - the genre might as well be called 'gun porn') only to be denied access (or killed) by his own people.