Where would violence come from? Austrian commandos storming the Federal Reserve? A nuclear exchange between Mt.Gox and Paypal?
I don't see it.
^^ This is funny. I get this mental picture of Mises and Hayek storming the Fed in ninja gear. I award you +1 internets.
I am not aware of any entities that have a monopoly on force.
What if I add "within a specific geographic location"? Can you think of any entities that have a monopoly on coercion and compulsion within a specific geographic location?