Apparently, the deposits were being given to a third person. Actual Customer was giving money to "Angry Customer," who was pulling up in the bank parking lot and allowing a younger family member to come in and make the deposit.
Angry Customer, as it turns out, isn't even our customer.
We never heard anything from our Actual Customer.
The way I see it, Actual Customer had the right to be upset, but Angry Customer was way out of line. Not to mention that as it turns out, Angry-Not-Actually-A-Customer accused our teller of giving the balance to the younger family member because she was trying to FLIRT!

Completely, absolutely, ridiculous.
Maybe that's the reason my manager changed her mind - the absurdity is baffling.