Some people in polite parts of the country have a hard time ending a conversation if the other party won’t let them/follow the local social protocol (not being sarcastic).
When I was a bachelor, that was my strategy. Still annoying, but at least I avoided the confrontation. Now I have a couple youngish kids and more often than not knocks at the door mean friends coming over, so they end up answering without checking first and then I get called to deal with the stranger at the door.