My answering machine say, Sorry, can't get to the phone right now. Leave a message. If it's important, call my cell phone.
Of course, unless YOU are important to me, you don't have my cell number, unless you are one of the jerks who calls to tell me you can reduce my credit rate. However...I have an option...REJECT. After that, you can call to your heart's content, and my phone will not ring. I look all these unknown numbers up on Google, NEVER call them back. You will see listings of who they are, what they wanted, etc. I figure if it was important, I will have a voice mail, right?
As far as answering the door? Four doxies will be happy to run there when the bell rings and announce there is someone at the door. I don't run for anyone. I am sure they can hear me yelling, ALRIGHT! I'll GET THE DOOR! I am sure it is NOT FOR YOU!! Anyone trying to sell me something just can't compete with four hounds in full voice, lol...so I let them talk...the hounds, I mean. My baby, Molly, will put a full grown wolf to shame, my little howler.
I used to be a Scout leader. We often took our kids out to go door to door for one reason or the other. I would watch other groups or individuals who would ring the bell, and if the door wasn't answered immediately, just turn and dash off to the next house. I told my boys to think about it, and pretend it was their grandmas and ggmas who were coming to answer. No one took off until they were sure no one was home.