[dragonwriter]

California has a very high minimum standard for am arbitration agreement to validly cover fair employment claims, including the employer covering all arbitration costs (irrespective of outcome), where they would not have to cover all court costs unless they lost and the employee was awarded costs. Armendariz v. Foundation Health, 99 Cal.Rptr.2d 745 (2000) [0]

I wouldn't be surprised if an employer chose to leave claims to which those rules apply out of the coverage of any arbitration agreement; leaving the employee on the hook for court costs is probably a better discouragement to claims, especially meritless ones, than arbitration is.

[0] https://scholar.google.com/scholar_case?case=160495945137091...