I think it's important to state exactly what's wrong with this concept of everybody submitting to authority only voluntarily. What's wrong with it is that if you don't want rules, if you want people to make do without them, then you have to have a pretty strong social ethic and that ethics must have, at the heart of it, the understanding that you do not readily do things that upset, distress or anger other people. If you do, there will be disputes, and hence, to resolve them, the requirement for authority to resolve them, with the expectation on all sides that this authority will be respected.
Now it's maybe just possible to believe that even in a complex and heavily-populated society, disputes will be relatively few because the habit of mutual respect and conflict resolution will be something we learn. I don't remotely think so, by the by, but let's accept it for the moment. However, as I say, we must have, at the heart of it, the conception of avoiding disputes by trying not to impose on or disturb other people.
Now, it strikes me that actually, a lot of people will not do this, a lot of people will not accept it or understand it and that prominent in their number will be "anti-authoritarians". Because in fact, the main instiinct of "anti-authoritarisn" is not to avoid disputes but to pursue them by insisting that they do what they want to do, that it is imperative that they be able to do what they want and that attempts to restrain them from doing so are "authoritarian". You can see this, as it happens, pretty much daily in this very place: "anti-authoritarians" insisting on their right to do their thing in their way. Whereas in fact, the only way voluntary association can work is if people are in the habit of not doing that, of deferring to other people, of backing down. In practive, "anti-authortarians" are the people who will disturb the social peace and fail to respect the social ethic.
"Voluntary association" is a non-starter, and one very good reason for this is the intransigence and propensity to disruption of the "anti-authoritarians". It's a point that they will never understand.