I did some contracting at a bank and an employee told me about a problem they had with their pneumatic tubes: A customer had taken the carrier with them when th

I did some contracting at a bank and an employee told me about a problem they had with their pneumatic tubes: A customer had taken the carrier with them when they drove off, so the teller put their spare into the tube and continued working. A short while later the customer realized they had absconded with the carrier and returned to the drive-thru and put it back into the tube. The next customer put their deposit in the carrier and sent it off - the teller received it and said "Sir, there's nothing in here." and held up the empty carrier to the window to show them. And sent it back. The customer took the carrier out, held it up to show his documents in it, and sent it back into the bank .. only to arrive empty again. They eventually figured out there were two carriers in the tube.