If they knock on my door they will meet a giant 6”5”, 340lbs naked guy (With a gun in one hand behind the door) and a 100lb pissed off pit/lab mix.
If they can read the sign at the door they will not knock, other than that, I can’t help them.
Years ago I used to have a small sign beside my front door that read, “No sales, no religion, uninvited persons leave now”. Only had a few people still ring the doorbell trying to sell something. I’d just point to the sign and shut the door.