It couldn’t have been considered a booby trap, legally speaking, because it was a mailbox and was harmless for normal operation and traffic. I
But it kinda was a booby trap. Guy was tired of his mailbox getting smashed, concrete, 8" steel pipe, railroad tie head, I don't think he was going to killing the guy or even hurting, but it had happened many times and he knew it was a matter of time before it happened again.
They driver was clearly in the wrong. the box owner imo clearly had intent.
don't get me wrong, i'm not mad it went down that way, fucking driver was a dickhead and playing stupid games, I would rather the mailbox just destroy the truck and taught him a lesson.