DEAR MISS MANNERS: Is it rude not to get up and unlock/open the door for someone who lives in the house and is returning home?
GENTLE READER: It is not impolite to assume that those living in the house can, and will, admit themselves. It is impolite to ignore evidence that they cannot get in, or cannot do so easily or without mishap. Examples include torrential downpours, arms full of groceries or a knock on the door.
As a matter of familial harmony, Miss Manners also cautions against remaining on the couch, visible through the window, while your spouse struggles to find the keys.