Fledermaus, I have lived in East Tennessee my entire life (48 years) and have never heard this. I can't imagine it being true. In fact, I have served on juries for murder charges where the defense was self-defense, and the only standard I recall was that the defender must have had a reasonable fear of death or significant bodily harm (speaking from memory here). As a jury, we were instructed that an individual could not use deadly force to protect property. Do you have some source for this? I'd hate for something bad to happen to another person or to you because there was an assumption about the law that wasn't true.
It was my understanding, as taught to me by my father, that as long as we have "No Trespassing" signs posted we have the right to act.
If not, I stand corrected. Of course I'd personally never just shoot anyone for being on my property. But my definition of "fear of harm" when it comes to liberal thugs is probably not as defined as the law! ;-)