Cal. Pen. Code § 630
The Legislature hereby declares that advances in science and technology have led to the development of new devices and techniques for the purpose of eavesdropping upon private communications and that the invasion of privacy resulting from the continual and increasing use of such devices and techniques has created a serious threat to the free exercise of personal liberties and cannot be tolerated in a free and civilized society.
The Legislature by this chapter intends to protect the right of privacy of the people of this state.
The Legislature recognizes that law enforcement agencies have a legitimate need to employ modern listening devices and techniques in the investigation of criminal conduct and the apprehension of lawbreakers. Therefore, it is not the intent of the Legislature to place greater restraints on the use of listening devices and techniques by law enforcement agencies than existed prior to the effective date of this chapter.
Ca. Pen. Code § 630