If you signed one of these and hack on the side… successful business could be owned by your previous company.
You can always ask that they release the IP which requires the lawyers to officially sign it over to you.
Before you quit your job make sure you own it.
i.e. your employer can require you to assign the invention to them if it's done during work hours OR with company equipment OR related to the company's business.
The full text in the California labor code is here:
https://leginfo.legislature.ca.gov/faces/codes_displaySectio....
Yes if you invent the next google in your spare time you could be in trouble. For this it’s best to get funding. At the lifestyle income level, your employer doesn’t have the time or money to waste on your passive income stream.
Obviously don’t be cavalier about it, but this will just get you fired not sued.