State v. Ferrier
In State v. Ferrier, 136 Wn.2d 103, 960 P.2d 927 (1998), the Court adopted the standard of the New Jersey Supreme Court, which held that "'where the State seeks to justify a search on the basis of consent it has the burden of showing that the consent was voluntary, an essential element of which is knowledge of the right to refuse consent.'" Ferrier, 136 Wn.2d at 116.
The court went further to state the obvious--that the only sure way to give such a protection substance is to require a warning of its existence.
If we were to reach any other conclusion, we would not be satisfied that a home dweller who consents to a warrantless search possessed the knowledge necessary to make an informed decision.
That being the case, the State would be unable to meet its burden of proving that a knowing and voluntary waiver occurred Ferrier, 136 Wn.2d at 103.
In light of that barrier, we adopted the rule that "article I, section 7 is violated whenever the authorities fail to inform home dwellers of their right to refuse consent to a warrantless search." Ferrier, 136 Wn.2d at 118. Thus, when police officers conduct a knock and talk for the purpose of obtaining consent to search a home, and thereby avoid the necessity of obtaining a warrant, they must, prior to entering the home, inform the person from whom consent is sought that he or she may lawfully refuse to consent to the search and that they can revoke, at any time, the consent that they give, and can limit the scope of the consent to certain areas of the home. Id.