Going back a good few years there was a guy I worked with who decided to become a cheque for the day.
This chap stapled a cheque to his shirt as he wanted to understand the flow of dispatching a refund to a customer. He stood at a desk for over an hour until he got ‘picked up’ and keyed into the system, and then being whisked down to the mailroom to wait to be bagged and couriered across to another office, in a different county, where further admin (mostly checking) took place.
The flow showed that the cheque was handled by an admin team, 2 mailrooms, and travelled a total distance of 30 miles before being collected by the Royal Mail (or whomever) a day after.
The guy was discovered many weeks later in the banking system, but he’s never been the same since.