Self-defense laws a very clear on when lethal force can be used. Despite the well-armed Smart Houses on the Almost Human episode “Disrupt,” the lethal defense of property is never justified. What was surprising was the homeowners who were sued for a teenager killed trespassing in their property were not liable for the victim’s death.
When conditions are present which, under the law, justify a person in using force in defense of property, that person may use that degree and extent of force as would appear to a reasonable person, placed in the same position, and seeing and knowing what the resisting person then sees and knows, to be reasonably necessary to prevent imminent injury threatened to the property. Any use of force beyond that limit is excessive and unjustified, and anyone using excessive force is legally responsible for the consequences thereof.
CALJIC No. 5.43.
There is a difference with self-defense, which can allow the use of lethal force to defend a person when a person is facing death, serious bodily injury, forcible rape or kidnapping. See, Model Penal Code § 3.04(2)(b)(i).
There are situations where personal self-defense and defense of property overlap. However, this is not meant to be a green light for murdering people who trespass on property. As one Court explain by citing a text on criminal law: if the defender’s reasonable force in protection of his property is met with an attack upon his person, he may then respond by defending himself and then may be entitled to use force. Commonwealth v. Young, 271 Pa. Super. 59, 64-65 (Pa. Super. Ct. 1979), citing W. LaFave and A. Scott, Handbook on Criminal Law, § 55, at 400 (1972).
Such a situation would be fact specific, however opening fire at an unarmed trespasser would be unreasonable.
A homeowner with a home defense system that shot a teenager who jumped a fence would have no right to argue defense of property or self-defense. It would make more sense for AI Home Defense Systems to have speakers that yell “get off my lawn” then automatic weapons for fence hopping.
The trespasser in “Disrupt” had committed a crime by entering the homeowner’s yard, however the Artificial Intelligence home defense system shot the youth. As such, the homeowners would be legally responsible for the excessive and unjustified use of lethal force on the trespasser.
Could such defense systems be armed for those who are targets for kidnapping and receiving death threats? Yes, but the system would need to be able to recognize when someone trespassing actually had the intent to commit murder, serious bodily injury, forcible rape or kidnapping of the homeowner, meeting the specific requirements for “defense of others” vs the force necessary to remove someone property. That would be a very dynamic operating system that decides life or death. It would be….almost human.