The racecourse betting operators have requested that GST be imposed only about the commission/provider cost held because of the club rather than your entire deal with worth of bets designed (very similar to other legal gambling segments have spoken about GST on rake service fees rather than on turnovers). https://www.jackpotbetonline.com/nba-and-paddy-powers-fanduel-to-partner-on-u-s-sports-betting/