As I have noted before I check my bank statements. Once a decade or so I find an error. The latest example was earlier this week when I noticed my bank had for some unknown reason paid two of my checks twice. When I complained my bank assured me that this was a "rare event" and that they would fix things. And in fact the money is now back in my account. Although as I suspected would happen I have lost two weeks interest. But since this amounts to less than a penny I suppose I will let that go. As for how rare this is, the statement entries reversing the errors contained 10-digit reference numbers. 6 digits clearly indicated the date leaving a 4-digit sequence number. So it appears my bank has to correct thousands of errors every day. Probably this is still a small fraction of their daily transactions.
I will admit that I no longer try to verify that I being credited with the correct interest. Perhaps I should.
Should Theresa May Hold a Second Brexit Vote?
5 hours ago