How is this the parking lot owners fault? Jay was trespassing.
If you plant a land mine on your private property and a person trespasses and blows his legs off, it’s your fault (or at least a lawyer can make a good case that it’s your fault).
You cannot boobytrap your property against trespassers in a way that will injure them. That is not legal anywhere that I know of.
This was clearly going to get someone hurt at some point.
It’s not legal. I suspect there will be charges or a lawsuit, or both.