Permitting minors to enter barrooms or billiard rooms

If the manager or owner of any barroom, wherein beer, wine, or any alcoholic beverages are sold or consumed, or billiard room shall knowingly allow any minor under 18 years of age to enter or remain in such barroom or billiard room, where before such minor under 18 years of age enters or remains in such barroom or billiard room, the manager or owner thereof has been notified in writing by the parents or guardian of such minor under 18 years of age not to allow him to enter or remain in such barroom or billiard room, he shall be guilty of a Class 3 misdemeanor.