A party arguing that the reporter’s privilege has been waived generally has a high burden. As one California court explained,
Waiver requires a voluntary act, knowingly done, with sufficient awareness of the relevant circumstances and likely consequences.  There must be actual or constructive knowledge of the existence of the right to which the person is entitled . . . . There must be an actual intention to relinquish it or conduct so inconsistent with the intent to enforce that right in question as to induce a reasonable belief that it has been relinquished.
SCI-Sacramento, Inc. v. Superior Court, 54 Cal. App. 4th 654, 661, 62 Cal. Rptr. 2d 868 (1997) (citations and quotation marks omitted).
In an analogous case rejecting the argument that the defendant waived a First Amendment defense, a California Court of Appeal explained:
The First Amendment “safeguards a freedom which is the matrix, the indispensable condition, of nearly every other form of freedom.” Where the ultimate effect of sustaining a claim of waiver might be an imposition on that valued freedom, we are unwilling to find waiver in circumstances which fall short of being clear and compelling.
Ferlauto v. Hamsher, 74 Cal. App. 4th 1394, 1399-1401, 88 Cal. Rptr. 2d 843 (1999) (citing Curtis Publ’g Co. v. Butts, 388 U.S. 130, 145, 87 S. Ct. 1975, 18 L. Ed. 2d 1094 (1967)) (internal quotations omitted). In Ferlauto, the plaintiff argued that the defendant could “not assert the First Amendment as a defense to his claims because they knowingly and voluntarily waived those rights by entering into a confidentiality agreement.” Id. at 1399. But because the court found the contract at issue to be “imprecise and overbroad,” the court held that the contract was “an inadequate basis for a knowing and intelligent waiver of the [federal] constitutional right to freedom of speech.” Id. at 1400.