I would recomend a Rambo First Blood style spear trap. Nothing says stay away better than a good ole fashioned wooden spear to the lower torso.
Also when you get caught by the police for spearing someone, which you will get caught. Just start quoting random lines from Rambo.
Cop: What the hell were you thinking putting a spear trap in the woods like this?
You: They drew first blood sir, not me.
Cop: Son what the hell are you talking about? You just speared an innocent man hiking through the woods.
You: There are no friendly civilians!
Cop: Are you screwing with me son. Do you know how much trouble you in right now?
You: There wouldn't be no trouble except for that king shit cop! All I wanted was something to eat. But the man kept pushing Sir.
Cop: Ok I'm gonna go ahead and charge you with assualt with a deadly weapon and you can tell this to the judge.
You: In town you're the law, out here it's me. Don't push it. Don't push it or I'll give you a war you won't believe. Let it go man. Let it go.
After they figure out your just quoting random lines from Rambo you can just plead insanity. You'll get off with like 6 weeks in a mental institution but more importantly you have sent a strong message to any thieves out there in the community.