That is a good question. It would have to be consent from the owner of the claim. A court that doesn't respect the consent of the victim would not perform well in a truly free market for law. People would want to have a choice in how the law gets executed and would recognize that they own their claims of property damages on the perpetrator.
Discussion
The owner of the claim, the victim, could grab this claim from the court. It could be a cryptographically signed and validated document on the nostr protocol. It would give the bearer the right to enact up to but not exceeding the maximum penalty (which was determined in arbitration) on the perpetrator.
Having full control of this bearer asset, the victim could then sell it to anyone, including the court's preferred bounty hunter agency which could choose for you, or you can go and choose a specific individual or an alternative agency or open source billboard and bidding system, to execute the law.