Been to so many of these and similar events. The best was gate crashing a party for officials at BITEC from all the provinces. Just went in and sat at a table in front of the stage, us and a couple of Japanese, we had no passes. Security kept looking and were just coming over when the lights went down and the food and booze arrived, and kept arriving. Probably the Japanese made security think twice about possible loss of face. We went to see Jintara. Monk ordination parties, weddings, funerals, wai kru and even some concerts celebrating graduations, song releases etc have free beer, You only have to pay in beer gardens normally. The ones I don't like much are the 'Chinese table' events costs a fortune and they only ever pick at the food, hong tong is the usual there. Had an amazing concert near our house a few years ago with 3 stages, the Chinese tables, but better booze. Our waitress had to be carried off by 9.30, been downing the free drink as well!
Last school party I went to in Mrs home village school new year, free food and drink then they all went home at 11.45!