If you win a jackpot of $1,200 or more quite often after the casino verifys the win casino personnel will often show up with a form for you to fill. They will ask for identification and then have you fill out a W2G form which is a IRS form for gambling winnings. The casino will then report that win to the IRS so you had better declare it on your taxes. Also if you are under 21 they will not pay the jackpot as its illegal to gamble under 21 they will ask you to leave or even have security escort you out if you are not a hotel guest.