Many states have laws that deem unused gift cards abandoned property, which if left unclaimed for a certain period, can be taken into the state treasury's general fund, just like an unclaimed or abandoned bank account.

FORBES: Retail

If for any reason he cannot locate the customer after reasonable and documented efforts as agreed to in writing with FINRA staff, Prim shall forward any undistributed restitution and interest to the appropriate escheat, unclaimed property, or abandoned property fund for the state in which the customer is last known to have resided.

FORBES: After Borrowing From Customer, Stockbroker Ordered To Pay Restitution