[notahacker]

All de jure property ownership, as distinguished from de facto possession, is a privilege granted, regulated and enforced by the government. In the absence of government, I'm assuming copyright could be enforced by "protection agencies" against people without adequate defence against them in the same inefficient but brutal manner as they could uphold other purely paper-based "property rights" like contracts, debt repayments and ownership of the means of production.

In fact, they'd probably get so efficient at collecting the money from those without significant resources to spend on defence they wouldn't look too hard to see if copyright had actually been violated before sending their royalty demands. It would be like the current legal system, but with more pointed weapons.

The pipe dream of "truly free market" shares one property of communism: that of being so egregiously flawed in theory as to be impossible in practice.