The California Court of Appeal in AMN Healthcare, Inc. v. Aya Healthcare Services, Inc concluded just that, - customer list is not considered a trade secret when such list can be easily gathered from social media and through regular advertising and solicitation efforts. Further, where the employee's job is to recruit within a certain market segment, non-solicitation of employee provision was an improper restraint on the individual defendants’ ability to engage in their profession, in violation of California Business and Professions Code Section 16600. Whether courts will enforce such provisions going forward may turn on the industry in which the employee works and employee’s job function.
Overall the issue of non-solicitation and trade secrets remains to be a complicated subject largely depending on facts of your specific scenario. Call your trusted outside general counsel if you have any questions about that.