You can't defend against a perfectly-executed sneak attack. In any societal format.
"How to magically prevent all violence?" is not a problem to be solved. It's a straw man.
But also: I dunno, a personal drone swarm? Helmet? Don't carry your stuff around, or if you do, make sure it's all encrypted?
You started this convo saying you'd prefer barbarians raiding ancient rome to the roman state. So not a straw man- literal reality for hundreds of years. And yes, one solution is to have nothing to be stolen. Have fun with that freedom. Maybe you can find a cave to live in no one wants to take from you. Not sure a drone swarm will be viable in a world where there are no preemptive centralised rules against violence. A helmet might work, but the thugs might have bats?
> "preemptive centralised rules against violence"
The straw man part is the implication that "rules" mean "the thing doesn't happen". If course the thing still happens. If all we needed were rules and laws, democratic societies would need law _enforcement_ or militaries.
In a free society you would still have the preemptive rules against violence. When you step on my property, you are either trespassing or you are acting upon an open invitation from me that includes some contractual stipulations that you are agreeing to by entering.
