Any gambling winnings are taxable - regardless of the amount but there may not be withholding required, I think depending on the amount and/or the odds on the table game
You can deduct gambling losses but only to the extent of your winnings and I believe only if you itemize deductions. It won't stop them from withholding on the winnings if it meets the criteria, but you can probably get some of the withholding back when you file your tax return