As I said such cases are not universal, but there are several interesting examples of societies that are non-sedentary, and are distinctly egalitarian and even anti-hierarchical, an example could be the Mbuti. I think Flip's was a valid point, when looking at other cultures and even more so when looking at what we understand as past cultures, we are looking at them through our modern or 'post modern' understanding. Words like authority and hierarchy are imbued with our modern understanding of them, this is not to say that many tribal, small scale or non-agricultural, non-sedentary people are not or were not hierarchical, merely to say that those concepts are a facet of our understanding of our own society. Avoiding imposing ones own societal schema's and understanding onto the structures of another society is immensely difficult, which is why so called 'anti-civ' versus 'pro-civ' arguments are filled with potholes. The fact is that both those terms and understandings are flawed and largely dated, and whilst you may think it unproductive to avoid comparing cultures, it is something that is necessary to actually understand another culture in its own language. I think its just as unproductive to try and compare and classify cultures.