Could several people use the same voucher or code?¶

Yes. A code can be copied and shared, and the product may allow partial redemptions or record attempts from several accounts before one succeeds.

One secret can create several event trails¶

Forwarding, photographs, printouts, shared storage and group messages can distribute the same code. With partial redemption, successive users reduce one balance. With single-use products, failed attempts may still identify accounts, endpoints, IP-related data, merchants and times.

The first person found with the code need not have purchased it, and a successful redeemer may have received it from another person.

Reconstruct access and balance changes¶

Preserve each known copy and its communication context. Ask whether the product was transferable, reusable, partial or account-bound and obtain complete enquiry, attempt and redemption history.

Map remaining value after each success and compare communications for sharing, sale or instructions. Separate access, attempt, redemption and receipt of goods or services.