No person or vendor shall be subject to the penalties of this article for having sold or offered or exposed for sale in this state any seed incorrectly labeled or represented as to variety or origin when the variety or origin of such seed could not be identified by examination thereof, unless he or she failed to obtain an invoice, grower's declaration, or other document indicating variety and origin and failed to take such other precautions as were necessary or required to ensure that the identity and variety of the seed were as stated.