I agree with METE and Glen Myers on this one...never open a door to a stranger.
I have taught this to my kids when they were small. I have cautioned my wife especially since I used to travel quite a bit, and my cop friends all say the same thing. Now my son is a cop and he teaches the same thing to all his kids especially since they live in a rural area.
My wife will never use a gun to defend herself. I have given up trying. My dog and the panic alarm system near the door entry is the only hope of survival my wife will ever have if she opens the door to the wrong person.
Even after all the discussion my wife and I have had on the subject, we were traveling in our motorhome when I got tired and pulled into a truck stop to take a break. I heard a knock at the front door while I was lying down in the back bedroom. Incredibly my wife opened the door. I heard someone asking her for money. I grabbed my 12 gauge and ran towards the front of the coach. When that guy saw me coming, he ran for his car and beat it out of there. I was later told he was a panhandler that would disturb the truckers and anyone that pulled off the road to take a break.
May the Schwartz Be With You.