This isn't a new provision, and is reflected in most CA employment contracts. The problem is clause #1 - "Relate at the time of conception or reduction to practice of the invention to the employer’s business, or actual or demonstrably anticipated research or development of the employer". If you work for a big company - Apple, or Google, or even IBM - they tend to claim that their business is "anything computer relate…
Has that clause ever been actually tested in court? I can't think of any cases where one of the big companies went after moonlighting.