If any Tennessee wildlife resources agency officer or employee has reasonable cause to believe that a field has been unlawfully baited with grain or any mixture of any ingredients used as or for food purposes for the purpose of killing, injuring or capturing doves, then such officer or employee shall immediately post notices on such field in conspicuous locations that the field is baited and hunting is prohibited. If any such officer or employee discovers and fails to post such field in accordance with this section, no person shall be subject to prosecution for hunting on or over such field, notwithstanding any provision of this title to the contrary. The Tennessee wildlife resources agency and its officers and employees are exempt from civil liability in its actions in enforcement of this section.