California Code, Business and Professions Code - BPC § 19846

(a) Notwithstanding any other provision of law and except as provided in subdivision (b), a gambling enterprise that ejects or excludes an individual based upon Section 19844 or 19845 is not subject to civil liability for a mistake as to the grounds for ejecting or excluding a person if the ejection or exclusion was based upon a reasonable and good faith belief, after a reasonable investigation, that these sections applied to the individual in question.

(b) Notwithstanding subdivision (a), a gambling enterprise may not be relieved from liability for any damages arising from the means of ejection or exclusion.