I guess that Punk learned his lesson. He should have learned to respect adults, especially Elderly Adults and their property. I would have gone for a anti-personal mine myself.
One thing to remember is that you cannot do something by remote control or trap that you can't do in person. If you cannot legally decapitate a trespasser in person (highly unlikely) then you can'y set a trap to do the same. You'll probably end up in the same cell as the shotgunner.
I'm not going to quote all the people who mentioned that the old man should have had a fence, but I really wish folks would work on their reading comprehension.