Thank you Cozen O’Connor for alerting me. California’s Senate Bill 1241 was signed into law at the end of September. It will apply to employment contracts entered into, modified, or extended on or after 1 January 2017.
The Bill will feature in a forthcoming article that I am co-authoring with Jutta Gangsted. I have not (yet) studied the preparatory work in detail however the Bill immediately calls for comparative analysis with the EU’s’ approach to this particular ‘protected category’: what is a labour (employment) contract; how does ‘primarily resides and works in California’ compare with ‘habitually carries out his work’ and ‘domicile’; when exactly is a contract ‘modified’ (on this see for the EU, Nikiforidis). The starting point of both the California and the EU rules is the same: employees cannot be considered to really consent to either choice of law or choice of court hence any clause doing same will be subject to mandatory limitations.
(Handbook of) European Private international law, 2nd ed. 2016. Chapter 2, Heading 18.104.22.168, Chapter 3, Heading 3.2.5.