In what circumstances will a defendant be required to notify the police of a break-in under section 1531 of the California Criminal Code?

In the present case the information provided by the confidential informant that defendant possessed several firearms is insufficient by itself to excuse compliance with section 1531. We have recognized that one of the primary purposes of section 1531, in addition to the protection of individual privacy, is to prevent possible violent responses that might be aroused in a startled and fearful householder suddenly confronted with unknown persons breaking into his home for unannounced reasons. (Duke v. Superior Court (1969) supra, 1 Cal.3d 314, 321, 82 Cal.Rptr. 481, 462 P.2d 10.) The danger that such a confrontation will result in serious injury or death to the occupant, police officers, or innocent bystanders is obviously intensified when the householder is in possession of a firearm. Thus, where the police are aware of such a weapon, the case for requiring them to give notice of their authority and purpose becomes more rather than less compelling.