It would seem that if you use their kitchen and facility, you become a contractor or personal chef for the event. In most cases, "occasional" outdoor cooking is not a problem. Might be best to have the bar owner approach his Health inspector to ask the question.
Rancho To Go BBQ Catering
Spicewine BBQs - West (Left) Coast
Large Spicewine - Ol' Blue
Twitter - @ranchoagogo @ranchotogobbq