We had a customer call and express concern about opening a checking account because she said that she heard about a recently passed California law which states that customers can be liable for something like 20-30% of the amount in the event of a lost/stolen situation. Any guidance on what I can tell her as far as the law/regulations are concerned, and how much she could be liable for?

I am not aware of any recent changes in this area.

Take a look at California's UCC section 4406 regarding customer liability for failure to notify the bank.