It is interesting. I found the following on a quick search in Lexis-Nexus.
§ 51. Citation of section; Civil rights of persons in business establishments; Definitions
(a) This section shall be known, and may be cited, as the Unruh Civil Rights Act.
(b) All persons within the jurisdiction of this state are free and equal, and no matter what their sex, race, color, religion, ancestry, national origin, disability, medical condition, marital status, or sexual orientation are entitled to the full and equal accommodations, advantages, facilities, privileges, or services in all business establishments of every kind whatsoever.
There is no single test for determining whether an establishment is in fact a private club or organization, and thus outside the scope of the Unruh Civil Rights Act (CC §§ 51 et seq.). However, selectivity is the essence of a private club. When there is a large membership or a policy of admission without any kind of investigation of the applicant, the logical conclusion is that membership is not selective. An organization with no limits on its membership and with no standards for admissibility is too unselective in its membership policies to be adjudicated a private club. This approach, focussing on exclusivity, ensures that private organizations remain protected. However, entities which are not in fact private must comply with the mandate of the Unruh Act. Curran v. Mount Diablo Council of the Boy Scouts (1983, Cal App 2d Dist) 147 Cal App 3d 712, 195 Cal Rptr 325, 1983 Cal App LEXIS 2233, 38 ALR4th 607, appeal dismissed (1984) 468 US 1205, 104 S Ct 3574, 82 L Ed 2d 873, 1984 US LEXIS 2805.
The inclusion in the Unruh Civil Rights Act (CC § 51) of the words "all" and "of every kind whatsoever" in referring to business establishments, without any exception and without specification of particular kinds of enterprises, leaves no doubt that the term "business establishments" was used in the broadest sense reasonably possible. The word "business" embraces everything about which one can be employed, and it is often synonymous with "calling, occupation, or trade, engaged in for the purpose of making a livelihood or gain." The word "establishment" as broadly defined, includes not only a fixed location, such as the "place where one is permanently fixed for residence or business," but also a permanent "commercial force or organization" or "a permanent settled position (as in life or business)." Rotary Club of Duarte v. Board of Directors (1986, Cal App 2d Dist) 178 Cal App 3d 1035, 224 Cal Rptr 213, 1986 Cal App LEXIS 2722, aff'd (1987) 481 US 537, 107 S Ct 1940, 95 L Ed 2d 474, 1987 US LEXIS 5218.
All of this is well and good, but it's more talking about excluding membership based on age, sex, and gender. Once a person is admitted as a member and essentially passed a private organization's "selectivity" rules, should that member not have all access to the rights associated with membership (assuming there are not different levels of membership that provide for access to certain events in the non-profits bylaws)?