I'm shocked no one has tried it.
Regardless of the fact the guy is a complete moron...I believe
that Maine castle-laws would permit him to open fire on someone if they are on his property w/ the intent to commit crimes against life or property. Well, after giving a verbal warning and allowing the person a chance to GTFO first.
He seems like the type that would put a couple of rounds in someone, then drop a knife beside their corpse and claim the intruder was brandishing it and making verbal threats against his life.
He's annoying and stupid...but not worth risking life or limb over. Thats likely why nobody has tried it.
On the reverse side of things, I personally wouldn't risk a prison sentence over shooting someone trying to steal my aluminum sticks...but thats just me)