A license holder or an agent or an employee of the license holder may not allow an individual under the age of 21 years to loiter about the premises for which a Class B or Class D beer license is issued. An individual under the age of 21 years may not loiter or be a nuisance on the premises for which a Class B or Class D beer license is issued. A person who violates this section is guilty of a misdemeanor and on conviction is subject to imprisonment not exceeding 1 year or a fine not exceeding $200 or both.