Okla. Admin. Code § 45:25-1-4
When attending a trade show or festival, the location within the trade show or festival occupied by the winery becomes a licensed premises and extension of the licensed winery. The licensee shall set up and define an area contiguous to their booth space as a serving area where the wine is dispensed. Therefore, a 21 years of age and older serving area shall be established and a Type II sign stating "No Persons under 21 Years of Age Permitted In This Area of These Premises" shall be posted at the entrance to the serving area or bar top. The licensee may only serve the wine in the serving area. In the event that multiple winemakers are at the same festival, they may combine their 21 year old and older serving areas into one larger area as long as they are contiguous to the winemaker's booths.
Okla. Admin. Code § 45:25-1-4