No, they don't explain that. I don't think they explain that to accounts officers and are simply told to follow protocol. However, neither have I ever had to explain to any accounts officer how my mother came to be born under the name I just gave. I got the idea a long while back when my mother and my grandparents had accounts at the same banking institution as myself and their names aren't all that common. I was young and paranoid and under the impression that should someone hack into my acoount theirs would be a mere name search away.
One day I lost my purse and had to replace everything, which meant closing the accounts and opening new ones. The rep at the bank didn't even blink when I gave her what to put in there, and I haven't given anyone my mother's maiden name since.

I do think people in general are becoming a bit more savvy when it comes to security, as I have been experiencing with the people I work with. Unfortunately for the banks and financiers it's a case of using the latest technology for antiquated protocols and that's what scares me.