so far from what you've said, i've gathered that your society completely depends upon all individuals being rational and nonviolent beings. In other words: your society depends on everyone not committing crimes, because if anyone does, there is no effective enforcement.
What is preventing people from hiring security? The same thing that's preventing people from doing that today: money.
You're also underestimating every criminal's ability to shoot, and overestimating bystanders' abilities to shoot.
And I don't know why anyone would want to live in a society like that. Where you are expected to kill people to defend yourself, or watch out for agressors in case you need to kill someone in defence of someone else.
What is preventing people from hiring security? The same thing that's preventing people from doing that today: money.
You're also underestimating every criminal's ability to shoot, and overestimating bystanders' abilities to shoot.
And I don't know why anyone would want to live in a society like that. Where you are expected to kill people to defend yourself, or watch out for agressors in case you need to kill someone in defence of someone else.