Understandable, but at what point do you conclude an intruder is no longer a threat? I prefer to be proactive in defense rather than reactive; it gives me more options and a greater chance of survival.

Better to err on the conservative side, and just assume that if someone has broken into your home, it is with the intent of doing you and yours great harm. You are certain, then, not to be unfavorably surprised, and still remain justified in your actions.

Nonetheless, I agree that the best time to warn an intruder you are armed is when the sear lets go.