Look at your African nations, middle east and even Asia as governments fell there was always a group that banded back together for the common good of the group. It may take years but no people want total anarchy and by that I take this definition, absence or denial of any authority or established order. Had many of those places been left alone and not had to deal with foreign influences, foreign armies, contrived puppet governments it's my opinion even places like Somalia would have stabilized far sooner than they have.
But surely thats the point. Your society will never be "left alone" because you have violent groups inside your community that want to have their own way and you have other societies who see a weak defenceless society and set about exploiting it. You need a police force and courts for the internal enemies and you need some kind of army to deal with external aggression.
No that's not the point. You argued that people would run amok, I said they wouldn't. You have proven my point in fact that people will ban together and self govern.
I also do not accept your premise that you must form courts, an army a police force. We do those things in our society so a handful of people are responsible for the safety of others vs. the society itself being responsible for it's safety. We do this because it would obviously be impossible for a nation of 300 million to hold court but mainly because we are fat and lazy and want others to do this for us. We hire a bunch of uneducated 18 year olds to wage our wars, note I said wage our wars as we (The US) are the aggressor and have been in almost all cases of wars fought by this country. We hire uneducated bullies to run our police in order to protect the assets of a few and to keep the deviants inline where my premise is that if society was self policing those deviants would not exist or would be driven out of the society and as I said would certainly not constitute 4.2% of our population.
Take a look at countries such as Costa Rica, no standing army, in fact it was banned 60 years ago and yet that society ranks as one of the highest in Socioeconomic growth. They are bordered by two countries which have a history of corruption and revolution yet it has not caused the fall of Costa Rica. Switzerland is another, although not perfect, example of a society governing itself. You have a direct democracy where anyone can challenge the laws meaning the laws are written by the people in essence as well as a citizen army in that everyone (males) must serve to protect the society as a whole. Switzerland has been surrounded by aggressor armies for hundreds of years yet they have maintained their society, not had to wage wars (although one could argue they wage monetary wars) and as a perfect example of society banding together for the good of society they are the birthplace of the Red Cross.