Section 2870 of the California Labor Code protects an employee's ownership in personal inventions so long as these inventions are
... developed entirely on his or her own time without using the employer’s equipment, supplies, facilities, or trade secret information ....
How is this provision affected in a work/live arrangement where the employee spends his after-hours (personal time) and nights at the office and wants to continue working on personal projects during that time? Would this constitute "use of employer's facilities and equipment" (rooms and internet connection) and thus invalidate the provision (i.e. any inventions made during that time will become company property) or is such use an understood subletting agreement in which these facilities effectively become the employer's personal space?
If such a living situation would compromise 2870, is there an example for a solid legal addendum that the company and employee can sign to protect the employee's ownership of personal intellectual property?