If revenue bonds are proposed to be issued, the ballots cast at a bond election shall contain a statement to the effect that the bonds shall be revenue bonds payable solely from the revenues of the district or a designated portion thereof, and that whether or not all of the revenues of the district are to be applied to the bonds, the bonds shall never be a lien or charge upon any land or other property in the district, and no tax or assessment shall ever be levied or collected to pay principal or interest on the bonds.