I recently deposited a check at the bank. The check was to be my spending allowance while on a business trip, so I needed to return any of the money I didn't use. After a week, I noticed that there was still no record of the deposit on my online statement. Concerned, I stopped by the bank. They looked it up in their system, only to discover they had accidentally put the money in someone else's account...
Luckily they were able to get the money back into *my* account before the end of the day, so that part is good service. But still, I had my account number and my name on the deposit slip -- how did they manage to give my money to someone else??