Not so long ago, I thought, and likely wrote, that a hunter-gatherer society would be perfect for the libertarian - no laws, no government. Boy was I wrong.
Actually, such communities are governed by very strict moral codes, inculcated by the community, and enforced, if necessary, with the ultimate sanction. A fundamental pillar of these codes is one that would offend every libertarian impulse - mandatory sharing of some crucial goods and resources.
A key fault line in certain moral debates in modern society - for example, gay marriage - is controversy over the impact of changing the rules. Conservatives claim, for example, that gay marriage fundamentally undermines traditional marriage. Progressives mostly consider this claim ridiculous, arguing that it couldn't possibly affect anybody but those involved - namely, gays who would like to marry.
Even though I take the progressive point of view on marriage, I think that the conservatives are fundamentally right as to the effects. Morality is everywhere and always a community concern and highly dependent on a community consensus. Upending community standards on something as fundamental as marriage must inevitably propagate in unpredictable ways through the whole structure of morality.
That doesn't mean that we should cling to every standard of morality we inherited from our grandparents or more distant relatives, or from some old books written a couple of thousand years ago, but it does mean we need to be conscious of the fact that we are tampering with very fundamental underpinnings of society, and we need to be concerned with their implications.