Awesome post, really enjoyed reading your experience.
Our children are indeed learning from these experiences, which is good–but ideally, learning ought not to happen at the expense of others!
So, does unschooling truly mean a free-for-all, or are there natural, inherent limits within the unschooling experience?
I think the important part is what you said, that they're learning from it. When they're restricted and punished, they don't develop a real capacity to understand their actions and the effect it has on others. (They only learn that there's this rule, and it hurts or they have to go in the corner or something when they break it. They don't learn how to actually relate to other people and what the real consequence is.)
Ideally not happen at the expense of others? Eh. It's a two way street. The other person learns too, and may learn something about expressing their problem and why it hurt them or whatever and about how to forgive and move forward. (At least, if they're unschooled themselves. If they're poorly parented then the parent will probably dominate the situation and it's different.)
I think clearly you don't allow them to eat glass or play too rough or do whatever would be physically harmful. (And even then they probably just agree with you and see why it's a bad idea. But you'd physically stop them if you needed to.) But that's pretty much it.
I think also important: Disciplined kids are guilty of this stuff too.
And they're probably way worse. If you look at any public school, it's not like there's a lack of fighting or kids being awful to each other :)
That's kind of the paradox of "discipline", that it doesn't actually work anyways. It's basically just a dependency on punishment and on the parent to always be looking, like managing the situation of the kids not having their own radar, and there will be some really bad outcomes (especially because they have the example of hitting and yelling being the way to get along).
But for some reason it's easy to blame unschooling for any little issue, yet nobody blames discipline for those kids' issues.
So I think kids being a little rough around the edges on their path to maturity is just how things are and can't really be eliminated. But unschooling is the best opportunity for them and the softest cushion.