In Duke v. Superior Court (1969) 1 Cal.3d 314, the court hypothesized that "had the police entered a house in which people are sleeping without first knocking and stating their authority, the occupants may be awakened by the sound of intruders breaking down the front door and moving through the house. The frightened homeowner might respond by attempting to protect his home and its occupants; he might thereby provoke an unnecessary conflict with the police." ( Duke v. Superior Court, supra, 1 Cal.3d at p. 320, fn.6.)