If a licensee or his agents or employees believe or have reason to believe that a sale or delivery of any alcoholic liquor is prohibited because of the age of the prospective recipient, he shall, before making such sale or delivery, demand presentation of some form of positive identification, containing proof of age, issued by a public officer in the performance of his official duties.
Proof that the defendant/licensee or his employees or agent demanded, was shown, and reasonably relied upon such written evidence in any transaction forbidden by this section is competent evidence and may be considered in any criminal prosecution therefor or in any proceedings for the suspension or revocation of any license based thereon. (235 ILCS 5/6-20)