Receipts.
(1) The liability of the owner or operator of refrigerated lockers for loss of goods in lockers or in operator's care shall be limited to negligence of operation or of employees.
(2) Persons who own or operate refrigerated locker plants shall not be construed to be warehousemen, nor shall receipts or other instruments issued by such persons in the ordinary conduct of their business be construed to be negotiable warehouse receipts.