138.7. A supply made by a charity of an admission in respect of a place of amusement at which the principal activity is the placing of bets or the playing of games of chance is exempt where(1) the administrative function and the other functions performed in operating the game and taking the bets are performed exclusively by volunteers; and
(2) in the case of a bingo or casino, the game is not conducted in premises or at a place, including any temporary structure, that is used primarily for the purpose of conducting gambling activities.