 The second factor that complicates recourse to due compensation for unconsented to boundary crossings is the fact that the best procedure for identifying the due compensation for a crossing is to require antecedent negotiation with and consent by the party who will be subject to the crossing (63–65). The best way to identify the due compensation for A for having her forearm broken by B is to see what payment A will accept to allow B to break her arm. However, this requires the prohibition of the boundary crossing under discussion unless the subject of the action agrees to it. When antecedent negotiation between subject A and actor B is feasible, the best route to due compensation for A (which is required under the liability rule construal of A’s right) consists in treating A’s right against B’s proposed action as a claim that is protected by a property rule. Especially since antecedent negotiation between subjects and actors is usually feasible, even rights that are in themselves only protected by liability rules are usually to be treated as boundaries that may not without consent be crossed.