Scenario 1:
You walk into a bank with a £10 note.
You: Can you change this £10 note for me?
Bank: Certainly, Sir. How would you like it?
You: Ten £1 coins please.
Bank: Certainly. There you go. Thank you.
You walk out of the bank with £10.
This is normal behaviour for a bank.
Scenario 2:
You walk into a bank with a £1 coin.
You: Can you change this £1 coin for me?
Bank: Certainly, Sir. How would you like it?
You: Erm.... Sixty-five thousand, five hundred and thirty five £1 coins please.
Bank: Certainly. There you go. Thank you.
You walk out of the bank with £65,535.
If this happens the bank has a bug in it.
