Sec. 12. (1) The revenue raised by an authority may be pledged, in whole or in part, for the repayment of bonded indebtedness and other expenditures issued or incurred by the authority. (2) A financial obligation of an authority is a financial obligation of the authority only and not an obligation of this state or any city or county within a public transit region. A financial obligation of an authority shall not be transferred to this state or any city or county within a public transit region.