Cal. Bus. & Prof. Code § 17538.45
(a) For purposes of this section, the following words have the following meanings:
(2) “Unsolicited electronic mail advertisement” means any electronic mail advertisement that meets both of the following requirements:
(f)
(3)
(A) In any action brought pursuant to paragraph (1), the electronic mail service provider shall be required to establish as an element of its cause of action that prior to the alleged violation, the defendant had actual notice of both of the following:
(4)