Thx so much for the quick - and clear - reply. I’m impressed by how well this community channel is used, thx to contributors like you!
Somewhere I was hoping, that a combination of data points on the ticket (transaction date, place, debit card + bank account screemshot, etc.) might make the ticket attributable to just one person (or family). In fact, there is also a QR code on the ticket, but probably readable only by Bahn-specific devices.
To stick to your analogy, something like trying to convince the cashier, that “this 20 Euro bill can’t logically belong to anyone else” 😉.
In any case, warm regards and wishing you all the best! 🙏