I think this is grey area as you could press trespassing and theft charges if they did try to sue.

Personally, I would have some kind of outer proximity device to set it off outside of my front porch.
I am not a lawyer, but I believe you are incorrect on that. If I'm not mistaken, it's not just a civil issue that they could sue you over. I believe that booby traps are a CRIMINAL issue. It's big time against the law. It's a felony.
I asked Grok: It's not even a gray area. You do it, and someone gets hurt... you're fucked. Felony!
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is booby trapping your property against the law?
Yes, in virtually every jurisdiction in the United States (and most other common-law countries), intentionally setting a booby trap to injure or kill trespassers is illegal, even if the property is clearly posted, you have “no trespassing” signs, or you’ve had repeated burglaries.The classic legal principle is: you may not use greater force than is reasonably necessary to protect yourself or your property, and you may never set a trap that acts without human judgment.
Common criminal charges you can face for setting injurious booby traps
- Aggravated assault / assault with a deadly weapon
- Attempted murder / assault with intent to kill
- Felonious use of an explosive device (many states)
- Wanton endangerment / reckless endangerment
- Booby trap statutes (specific crime in many states — e.g., California Penal Code § 20150, Florida § 790.16, Texas Penal Code § 46.04)
Bottom-line practical rule of thumb (U.S.)If the device is designed to automatically injure or kill a person who enters your property without any further human decision-making, it is almost certainly illegal in the United States, regardless of:
- how many times you’ve been robbed
- how many “no trespassing” signs you have
- whether you live in a rural area
- whether you warn about the trap
The law strongly prefers active self-defense (you decide to shoot) over pre-set mechanical vengeance.Short meme-version summary most lawyers would agree with:
"Cameras, dogs, alarms, lights, locked gates — fine.
Anything that goes boom/boom/stab/shock/slice without you being there to say 'yeah that guy deserves it right now' — felony."
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TL/DR: Fun to watch fake videos of booby-trapped packages vs porch pirates. But do NOT do it! You will go to jail.