Here in sunny Louisville, KY, we have our own city ATF, (I used to work for local police installing radios, lights & sirens.) They would set up stings in local bars and liquor stores. On one occasion, they had an undercover op, looked young and had an underage id, try to purchase alcohol. She was turned down, then the agent walked in and claimed the bar sold the girl alcohol without checking her id. Tried to cite the bar.
My buddy I worked with told them that was not what happened and they had best not try to pull anything. (this was his home bar.) The agent got upset & tried to get some trouble going on with us, but they are sort of orphan stepchildren of the city agencies, so our boss told them to get stuffed.