Shuttle driver lost item policy: how do you avoid arguments after a trip?

Lost items sound like a small problem until the passenger is upset and the driver is being treated like they personally hid the phone. Shuttle work, hotel runs, airport transfers, medical rides, employee vans — it all happens. Somebody leaves a bag, wallet, keys, glasses, or a tablet in the seat pocket, then calls later convinced it has to still be in the vehicle. I think the best policy starts b…