I am under no obligation to answer the door, any more than I'm obligated to answer a call from an unfamiliar phone number. I live in a densely-populated, and economically diverse, area with all the grief that brings. I have a weapon either holstered or in my hand when I approach the door. I never open the door without checking out the other side. This is trebly so after hours. I do not entertain often, and never real late, so no one is likely to be calling with legitimate business. Any late-night conversations will be through a closed door.
"...A humble and contrite heart, O God, thou wilt not despise." Ps. li
"When law and morality contradict each other, the citizen has the cruel alternative of either losing his moral sense or losing his respect for the law." —Frederic Bastiat