I can’t imagine that’s required by law in any state.
But that’s not the point. Businesses install cameras to protect themselves (from employee/customer theft, frivolous lawsuits and to document their compliance with other laws) and their customers.
The fundamental question will be whether the jury believes the hotel provided adequate security/monitoring of their premises. If an area is supposed to be only for employees is there adequate security to ensure other people can’t access it? If/when they were alerted by her friends that she was missing was there an adequate response? Is there some sort of protocol that was or wasn’t followed? Did an employee run into her at any point? Has something like this happened before?
All this, not to mention 1000 other things will be hashed out.