As others have said, the mailbox and booby-trap laws aren't the same thing.

Setting aside basic morality for a second, and strictly from a societal organizational perspective of which is the purpose of law, they're incompatible with the reality of society.

For starters, there is literally nowhere you can put one that society has agreed is off limits in all circumstances forever, which is important because the nature of a trap is that they can survive longer than whoever set it.

Consider your neighbor witnesses you clutch your chest and collapse in your home so they call 911, and the first responders get blasted by a tripwire shotgun. Consider you get hit by a car and die, and your next of kin come to gather your belongings and meet the same fate. Consider you booby trap a basement closet, get dimentia, and your homecare worker gets blasted because you forgot you even did that when you were young and insane rather than merely old and demented.

By nature of a booby trap, you can't foresee who will trip it or why. You've surrendered contextual judgement. It strictly CAN NOT be proportional.