Swiss authorities have warned travelers against a scam that’s been pulled at several automatic ticket machines at Zurich’s rail station, and has been reported in other cities as well.
Scammers have figured out how to tamper with the machines so that bills inserted in the machines become trapped. The traveler then goes off to find help from station staff, or simply walks away, while the scammers retrieve the money from the machine.
It’s referred to as the “Marseille trap” because it was first reported there. Best advice (aside from reporting anyone you see tampering with the machines) is to stay with your machine and send someone else for help. Or avoid using significant cash in automated machines.