Idaho Code § 23-943
No person under the age of twenty-one (21) years shall enter, remain in or loiter in or about any place, as herein defined, licensed for the sale of liquor by the drink at retail, or sale of beer for consumption on the premises; nor shall any licensee of either such place, or any person in charge thereof, or on duty while employed by the licensee therein, permit or allow any person under the age specified with respect thereto to remain in or loiter in or about such place.
Provided, however, it is lawful for persons who are musicians and singers eighteen (18) years of age or older, to enter and to remain in any place as defined in section 23-942, Idaho Code, but only during and in the course of their employment as musicians and singers. Provided further, that it is lawful for persons who are nineteen (19) years of age or older to sell, serve, possess or dispense liquor, beer or wine in the course of their employment in any place as defined in section 23-942, Idaho Code, or in any other place where liquor, beer or wine are lawfully present, so long as such place is the place of employment for such person under twenty-one (21) years of age. However the foregoing shall not permit the sale or distribution of any alcoholic beverages to any person under the ages specified for sale of alcoholic beverages.
Idaho Code § 23-943