No Trespassing sign ✔. How about answering the door with a bath robe. Glycerin streaming from your nose to give that juicy sick look, continually sneezing every time they start to speak. Then ask to see their ID and remove any face covering for identification purposes. "It's just allergies," as you take a bite from what is apparently food that has been off for a week and claim you can't taste a thing because of allergies. Overtly friendly, offering a handshake while transferring a hanky laden with ky from right hand to left in one smooth motion.