Everybody should feel comfortable in the space where they’re living. That’s why housemates should clear potential guests with each other because it creates a sense of trust. It’s never a good idea to bring random strangers into a house because it stirs up problems.
“Punk hippy housemate let two homeless alcoholics crash on our couch with their chihuahua,” ChuckDuck253 explained. “I got scabies from them and got to deal with that for six months.” That’s a disgusting problem to deal with.