I had a veteran city police officer tell me to always answer your door. Why? Because around here, our burglars knock on your door and if nobody's home, they pry the door off and waltz right in. So a burglary turns into a home invasion which turns into a kidnapping, rape, murder, or other personal assault. Now...what the officer did not say was OPEN your door. Where I live I get a lot of very suspicious looking "solicitors". I look through the peephole and yell "I am not interested". I know my neighbors well enough to know if it's one of them. Never had one press it after that. Both bases covered. Had one guy straight up pounding on my door. Very scary in fact. Night. Three guys...young guys. Way too late to be knocking on doors to sell anything. I grabbed my firearm and yelled "I'M NOT *&^@#$ INTERESTED" in a very gruff manner. Don't know what that was gonna be but it turned out, for me at least, to be nothing but a scary knock at the door. Never saw them again. So unless you're front door is Fort Knox-like, please think carefully about completely ignoring a knock with silence as it may be a "reconissance knock" if you will. But no, don't OPEN that door.