When checking out California Labor Code section 2870, also remember to check out California Labor Code section 2871, which expressly states that the restriction in 2870 does not limit the employer's right to require the employee to provide confidential disclosure of inventions during the employee's term of employment, and also to require a review process by the employer to "determine such issues as may arise" related to the disclosed inventions.

The "not related to your employer's line of business" is the tricky clause. With a large diversified tech conglomerate like IBM, Apple, or Google, they could conceivably argue that anything tech-related was in their line of business. They may not win, but you don't really want to fight one of their legal teams in court, and so it had a chilling effect regardless.

I'm not actually in CA I was just curious about CA laws because they seem to lean the most on the side of the employees compared to other states.