[park4bmx]

only possible, untrustworthy, way would be to keep an aye on the players money,once they raise you will know if they have won.

The check
Check their position and interior to make sure they are near a casino game, to make it more trustworthy/accurate make sure that no player/admin has given them any money while playing/not playing the casino game so the script doesn't mistake it for a game win.

only way i can think of.