Happens quite often in the states of the US where they have rules that basically allow you to legally shoot people straying onto your property.
IMO the idea that you have the right to kill people entering your home is exterme and, largely, impractical. Most people's thoughts when confronted with a intruder isn't to kill them, it's to
make them go away. Sufficient force to convince an interloper that leaving the property would be a better option seems perfectly reasonable to me. I've always had the idea of 'equivalent risk'. If you genuinely are in fear of your life - i.e. the intruder has a weapon - then you should be legally allowed to defend yourself as if in deadly peril. However if the intruder is not armed, then you taking a weapon and doing them in just strikes me as disproportionate reaction. Defend yourself, defend your property but where comes a point where you are acting in malice, not in defense.
Jon