At least, for this subject, the where, when, and/or "what reality" isn't an issue.
If a property owner has absolute right to said property, are they granted carte blanche to operate as they see fit with the property, and to defend their stake from involuntarily giving up said property? The short Libertarian answer is "yes", the asterisk to the answer is "provided they do not initiate uninvited aggression on another." Then what of defense against trespassers, burglars, or any possible villainy that might come to violate an individuals property rights? I'm hard pressed to demand that someone being aggressed against isn't allowed to respond, or has an obligation to discern motive and goal of the aggressor - particularly in circumstances where it's clear that the individual doesn't want trespass, such as breaking through a locked door or window. Insisting on such an obligation could cost a person everything.
What happens when circumstances are clear, and it's been discerned that life and physical well being isn't in danger? Does the owner have the right to operate as Judge, Jury and Executioner? Would he judge where property begins and ends? Would he impose the maximum value upon lost property, and perhaps the maximum penalty? Does this property owner define the minimum and maximum penalty?
Most importantly, is there a Libertarian justification for the property owner to act on these gauges of justice? Some believe so. I disagree. Others do as well, for reasons that are theirs.
In an earlier writing, I posed such questions - tackling the belief that the Property Owner has this right in the most extreme:
If I don't like the smell of cigarette smoke, and I can smell my neighbor's cigarette smoke wafting onto my property, am I within my rights to kill said neighbor for robbing me of air on my property that would otherwise be clean? Is my neighbor's wife within her rights to kill me for the loss of household revenue and the destruction of the family unit?
What if my neighbor's newborn won't stop crying at a time that's most disruptive, taking away my right to a peaceful property? Do I have the right to exact a righteous justice of my choosing, raising high my knife as I roar triumphantly for Anarcho Capitalism? Could I use a tiny nuclear device instead?
If a farmer has the right to shoot a juvenile apple thief, why not operate in the extreme for these scenarios? If this is the case, then where does the right to retaliate end? If there's a universal answer regardless of the infinite scenarios that carry a heavy weight, I don't have it. Even if I did, I wouldn't be within my Libertarian rights to impose it on the entire human population. Unless I'm a Libertarian central planner, and I enforce my rights by initiating force. But I thought Libertarians weren't necessarily champions of that.
But what happens when we answer in the affirmative to all of the above? I'd say there's no work left for such Libertarians to do, except buy the Champagne and choose where to host the party. Our goal is achieved, as there is at least one of such property owners, operating on funds they call theirs, all to inflict punishments for transgressions in extremes of their subjective choosing, steadfast in belief that their property lines end where their gaze does, and fully within their rights to enforce outrageous penalties on "aggressors".
We could go to Washington D.C, this property owner's base of operations, to host this celebration of Libertarian victory, then applaud and cheer for exercised property rights as we are incarcerated, or executed on sight by merit of their self-granted rights, for a transgression that the property owner believes happened and is owed infinite restitution.
I'd insist that we instead get back to the drawing board.