Ran across this piece of the Nevada gaming regulations that bears on that. The casino has to report periodically to Gaming the amount of their unredeemed slot tickets that have now expired. They get to keep 25% of the tickets value, while they have to pay 75% to the state general fund.

NRS 463.369 Records to be maintained; expiration of obligation to pay patron; quarterly report; payment of percentage of value to Commission; regulations; “slot machine wagering voucher” defined.

1. Whenever a nonrestricted licensee owes a patron a specific amount of money as the result of a slot machine wagering voucher which remains unpaid because of the failure of the patron to claim the value, regardless of whether the identity of the patron is known, the nonrestricted licensee shall maintain a record of the obligation in accordance with the regulations adopted by the Commission.

2. Unless the Commission specifies by regulation a shorter period in which a slot machine wagering voucher must be redeemed, upon the expiration date printed on a slot machine wagering voucher issued in this State or 180 days after a wager is placed, whichever period is less, the obligation of the nonrestricted licensee to pay the patron any value remaining on a slot machine wagering voucher expires.

3. Each nonrestricted licensee shall, for the previous calendar quarter, report to the Commission on or before the 24th day of the month following that calendar quarter any slot machine wagering voucher that expires pursuant to this section. The licensee shall remit to the Commission with each report payment equal to 75 percent of the value of the expired slot machine wagering vouchers included on the report.

4. The Commission shall pay over all money collected pursuant to this section to the State Treasurer to be deposited for credit to the State General Fund.

5. The Commission shall adopt regulations prescribing procedures which nonrestricted licensees must follow to comply with the provisions of this section.

6. As used in this section, “slot machine wagering voucher” means a printed wagering instrument, issued by a gaming establishment operating under a nonrestricted license, that has a fixed dollar wagering value which can only be used to acquire an equivalent value of cashable credits or cash.