If a casino patron wins an unusually large amount of money, the casino may take certain steps to manage the situation. This could include closely monitoring the player's activities, reviewing the game's integrity, and potentially limiting the player's future access to certain games or the casino itself.
Gambling winnings are fully taxable and you must report the income on your tax return. Gambling income includes but isn't limited to winnings from lotteries, raffles, horse races, and casinos. It includes cash winnings and the fair market value of prizes, such as cars and trips.