Legal Question in Landlord & Tenant Law in California

So her mother now seems to concede that her prior statement that you legally had to allow her to enter is not true. So why should you believe her second opinion? It is your business location and you can allow others to enter if you feel they do not present a risk or problem to you. Ask her for a written legal opinion, at no cost to you, as she will not be able to come up with anything that really supports her position. If she persists and will not be stopped iln her demands, tell her mother that as her attorney you will tell her that you have been told that her daughter might be doing inappropriate things and you have told her that, therefore you do not feel comfortable in giving her free usage of the premises. If she asks who made the accusations, just say it was someone who appears reliable and you can not reveal their name or names and are merely telling her in confidence since she asked for a reason. You should consider finding another person to take the daughter's place as she will likely be trouble in the future.

I would add that unless the mother is a licensed attorney, you might mention to her that she is committing a crime by practicing law without a license and we'd be happy to help you file a State Bar complaint and seek prosecution on that basis.