You’re assuming an intent to kill would manifest itself as an admission in court. Not likely.
You’re disregarding the variability of mailbox design. There is no reasonable expectation of the structural nature of a mailbox or of a safe way to strike it from a moving vehicle.
There isn’t an admission in most things. You do what you do in most cases. The jury sees a picture of the mailbox, hears an explanation from the owner as to why he put in there in the state it was in. They can hear testimony from his neighbor who he told “that’ll show the little fuckers” as he was mixing the concrete. The jury then decides from themselves if the owner set a mantrap.
Maybe the guy gets away with it or is unjustly held liable. No different than anything else.
ETA: Now, at the bottom of the page are ads for mailboxes from Mailbox Superstore. 
I expect it to be what it appears. If it looks like it is a regular rectangle black mailbox on a 4X4 post, I expect it to be empty inside, ready to receive mail, not to be filled with concrete.
ETA: And again, there is no law saying I can’t have an extra sturdy mailbox, but if it is shown that I did it to injure or in reckless disregard of injury to kids who might swing a bat at it, then I am liable. If I argue that I have lived there for 30 years and no passing motorist has ever knocked it down, but storms often do, so that is why it is so sturdy, then maybe the jury credits that testimony.
< pedant > Venomous. A snake would only be poisonous if you got sick from eating it.
Yep. Additionally, in some states it is illegal to keep native species.
Since there is no law regarding the sturdiness of mailboxes then you would have presumed incorrectly. You would also be asked for some relevant expertise on the safety of hitting fixed objects from a moving car. The burden is not on the defendant.
Year ago we rented a house next door to a rather strange old guy who would go foraging in wild country down around the Missouri River for snakes to bring back to his property, apparently for rodent control purposes.
This did not make him immensely popular with Mrs. J.
Heh, most weekends we relocate a snake or two around our house. We want them in the barn, for rodent control, but my gf is squicked out that they’re around our house eating the toads and chipmunks that she likes. So one of my “chores” is grabbing any snake she wants moved, and relocating it.
I’m assuming that that is as successful (long term) as taking a cat off of the kitchen counter.
Yepper.
Domesticated house cat’s generally have to be trained to kill their prey.
The point was that, much like the cat will jump back on the counter the minute you leave the room (if not earlier), the snake will return to the yard where it can find prey (and Kayaker can rehome it again).
But that is the key difference. People that reinforce their mailbox have the intent to protect their property from damage while the trap set in the OP has the intent to cause injury. If we want to talk about reasonableness, the argument seems to be that a person that reinforces their mailbox reasonably expects the teenager to be injured while I think most expect the result to be knocking the bat out of his hands and maybe it stings a little. There seems to be little discussion on the teen having the (legalese) reasonable expectation of getting injured swinging at mailboxes from a moving car.
Plenty of others have tried to explain how the law actually works. It will not narrowly focus on the mailbox itself. It will not narrowly focus on whether it is illegal to reinforce an inanimate object. It will look at the context of the actions of the person causing the mailbox to be reinforced. It will look at es knowledge. It will look at reasonableness, likelihood, and expectations. The owner cannot hide behind a facade of ignorance that E is doing nothing but innocently reinforcing an inanimate object. If the context reveals that the owner knew that this was likely to function effectively as a booby trap, then that knowledge will be relevant.
And has been explained in detail there are mailboxes on the market that cannot be crushed. It doesn’t matter if it’s heavy gauge steel or cement that reinforces it. It’s not an active booby trap. the danger involved is not the mailbox, it’s the idiot swinging a bat from a moving vehicle.
Really, what don’t you understand about this? There is no safe way to do this. You can’t demonstrate in court that there IS a safe way to do this.
Let’s boil this down.
You can’t do things that you can reasonably expect are going to cause other people to get hurt. It’s as simple as that.
installing a heavy gauge mailbox does not cause people to get hurt. It’s inert. What causes someone to get hurt is the action of trying to hit it from a moving car. It’s no different than a steel door. If someone tries to hit it with a baseball bat or break it down with their shoulder and is injured it’s their fault and not the door or the person who installed the door. The intent is to stop the destruction of property and that’s how it would play out in court. There is no entitled expectation of the destructibility of property.
You can’t hit something from a moving car with a baseball bat with the expectation it’s a safe thing to do.
It’s as simple as that.
You missed the main point. You can’t do something that you should reasonably expect to cause someone to get hurt. Even if it’s inert. Even if their own actions lead to the injury. Because what you did exacerbates the injuries. You are still arguing about the way you think things should be rather than the way the law and the courts actually see them.
there is no legal basis for what you’ve said. People are entitled to build structures that resist damage. the intent is to resist damage. There is no legal requirement that it be safe for those who try and damage it.
I think, in a broad sense, that what others are explaining here is that if you expect that someone will try to damage it (and maybe even if you don’t, but should expect it), then yes, there is.