On August 14, 2014 the California Supreme Court held that if a person chooses to remain silent prior to being read a Miranda warning and the person does not expressly tell the arresting law enforcement officer that he or she is making the choice to remain silent, the Government may use that person’s silence as evidence of guilt.  Basically, a defendant must now clearly indicate that he or she is invoking their right to not speak by using language like, “I’m going to remain silent now,” or “I am hereby invoking the Fifth Amendment” during police questioning and prior to a Miranda warning for legal protection to apply.
The Court’s goals with this case are to avoid difficulties of proof at court and provide guidance to law enforcement officers. Making a defendant clearly indicate that he or she is invoking their right to remain silent will, in theory, let the Government know when a witness is relying on the privilege so there is less ambiguity with defendant testimony. The requirement will also give courts a clear view of a witness’ reasons for refusing to answer a law enforcement officer’s questions.
However, there are also concerns with this new decision.  First, the Court is giving law enforcement officers incentive to delay Miranda warnings after an arrest since that post-arrest silence may now be used to prove the suspect’s guilt.  This outcome circumvents the very reason that the Miranda warning was implemented, which is to protect the suspect’s Fifth Amendment right to refuse to answer self-incriminating questions.
Second, the Court is envisioning that a suspect, immediately after being arrested, will take the initiative to get a police officer’s attention and declare his or her desire to invoke the Fifth Amendment privilege, assuming the suspect has both the awareness and presence of mind to do so.
And third, the Court’s decision is a Catch-22.  With this ruling, if you say something incriminating to law enforcement your statements can be used against you, while at the same time if you have invoked your right not to speak but have not properly “spoken up” and told law enforcement of your intentions to invoke the Fifth Amendment privilege, then your silence can be used against you to.
Read the Court decision here: https://www.courts.ca.gov/opinions/documents/S202107.PDF