When we went to Ticket In / Ticket Out I wrote all the procedures for redemption of tickets, stolen tickets and such for two properties.
I will give you a little insight on what we do when a voucher is reported stolen. Did you know in many slot systems that the voucher can be tied to a players card number when it is cashed out from the slot machine? After the initial security/surveillance review, the slot department secures the serial number of the ticket and verifies the players card number.

The number is brought to the cage and redeemed (if it has not been redeemed).

IF THE TICKET IS NOT REDEEMED - Which is the case at least 50% of the time
1) We redeem the ticket and pay the guest.
2) We put the ticket serial number in a program (which I created) called TicketWatch - Which also keeps track of the date and other important information.
3) Since the ticket is now redeemed, the person holding the stolen ticket cannot use the ticket in the slots, redemption machines and will usually bring it to the cage.
4) When the ticket comes up to the cage, it will say that it is redeemed, when that happens we scan the ticket in TicketWatch to see if it is a stolen ticket
5) If it is a stolen ticket we will notify security and surveillance, and stall a bit telling the guest we are having a problem with the ticket.
6) At the point of security arriving - we explain that we have a stolen ticket and provide them the information from TicketWatch, they will take care of it from there.

Also surveillance will review the time the ticket was cashed out and see if they can find a suspect through video review.

IF THE TICKET IS REDEEMED
If the ticket is redeemed in a slot machine and the person who stole the ticket is using a players card, then we pretty much tracked them down. Security and Surveillance will do a video review and apprehend the guest - either at this time or their next visit, because they will be flagged.

If the ticket is redeemed without a players card in a slot machine or a redemption unit - we can get a report on the time, then surveillance can review the video and find out where the suspect has been. Tracing them to other slot machines and such, if they happen to use a card later we will have their name.

We capture around 95% of the suspects with our policies. This includes the suspects that leave and sell of the ticket or give it to a friend to redeem later. We have had many suspects pay restitution to the guest or faced going into the legal system.