(a) It shall be unlawful for any person under 21 years of age to remain on any premises where the sale of cereal malt beverages is licensed for on-premises consumption.
(b) This section shall not apply if the person under 21 years of age is an employee of the licensed establishment, or is accompanied by his or her parent or guardian, or if the licensed establishment derives not more than 30% of its gross receipts in each calendar year from the sale of cereal malt beverages for on-premises consumption.