Lethal security systems are flat-out wrong. No, stealing is "flat-out wrong." My life is a stretch of time from point A to point B. I willingly exchange a portion of that time in labor to create goods. Anyone trying to lay claim to the goods I have created is trying to lay claim to a portion of my labor, indeed a portion of my life. He can go straight to hell...
If he wants me to respect his rights to life, liberty, and property he'd best start by respecting mine. Once he takes the gloves off, the gloves are off...
Of course stealing is flat-out wrong. I never said otherwise.
That doesn't justify the use of lethal force, either legally or morally, by an absent property owner.
"Disrespect me and I'll kill you" might be the code in the Wild West or in the 'hood, but it has no place in a civilized society. We have police and courts to deal with lawbreakers. We don't need or want individual citizens setting themselves up as their own justice system.