I have about 37 years of teller/management experience in branch banking. I have seen both sides of this story. The difference is like someone mentioned, how the situation was handled, the words used, and the body language. I have had to call people to tell them of a mistake which was discovered after they had left the bank but we were prepared to eat whatever it was if the customer insisted we were wrong. Still, the call wasn't always in the bank's favor so what then, would we be so upset in that case? As for making the customer wait until the end of the day to balance the window, that's rediculous. We closed the window immediately upon something being questioned by a customer and balanced it with the customer standing right there if they wanted to watch. We always hoped they were right. Our customers as a rule had become our friends. Banks are not in business to rip people off.
Cath, when our tellers received cash, they punch in the total of each denomination so that there was a trace that matched the cash entry to the system. Our deposit slips have a space to list the individual denominations too. I would find out that manager's superior and let them have an earful too. If you can't trust them to correctly handle $40 you can't trust them with $400 or $4000. I would suggest you close your account as quickly as possible. I know it's hard to do because of the outstanding checks but if you keep good records and your statement is balanced every month, you will know what is yours.
As for balancing periodically throughout the day, that doesn't sound very profitable. It means a window has to be shut down and physically counted and totals run. I'm not saying we never did it but it was never mandatory. There would be no reason to do it periodically. We only did it to kill time or if for some reason we felt we needed to. It was up to the teller and whether she could squeeze it in without causing a problem for the other tellers and customers
Folks who say that banks don't make mistakes are silly. Banks aren't something that either makes or doesn't make a mistake. Banks are a company manned by people and PEOPLE make mistakes. I made plenty of mistakes in my career. The first person who should know this is a manager. Otherwise, why would the tellers ever have to balance their cash drawers? Why would there be a system of checks and balances throughout the whole banking system? Every department that handles anything that has to do with debits and credits has a balance system. And it is a real simple one: The debits have to match the credits EXACTLY. When they don't, something is wrong.
Of course there are ways to steal. I knew too much about the bank to have the guts to ever try it. Because if you really know what you are doing, you know that there are not "lots of ways" to get away with stealing from the bank. Either that or I'm just plain stupid. After all those years and seeing the efforts made to steal and not get caught, that didn't work, it just wasn't worth it. If that teller actually did steal the $40 and "got away with it", you can be sure the next time her window comes up short or this type of thing happens again, the manager or her fellow workers will remember it and she's a done deal. You don't "get away" with it long. The bank doesn't prosecute for piddly stuff like that and I don't think they are allowed to say why that person was fired but most people can put 2 + 2 together and figure it out.
As for banks not being able to keep accurate records, I don't understand why that could ever happen. Whenever an error is made, it is right there on our statement from day one, in black and white. I have balanced hundreds of checkbooks in 37 years when customers needed help, to show them how to do it, and when they were out of balance. There never is a mistake made by the bank that doesn't show somewhere, somehow. Things don't just magically change without a trace or record at the bank. But you know what, they did in customer's checkbooks. Customers would come in complaining because they were overdrawn and when I offered to balance their checkbook, they admitted that they didn't have one or didn't know how, or didn't keep a balance on paper, just "in their heads". Or they would write down the checks and deposits and not have a running balance. Then all of a sudden, the "bank" was at fault. There are even ways that a personal computer program like Quicken can mess up and throw us out of balance. It's all up to us as customers to guard our money that is handled by financial institutions just as closely as we would in our wallets. And that is done by reviewing every receipt we are given, counting our money before we leave the window, and balancing our checkbook at least once a month. If you have computer access to your accounts, you can balance it every day if you like.
OK enough of my lecture.