A glitch?

CNN report that:

"A technical snafu left some Visa prepaid cardholders stunned and horrified Monday to see a $23,148,855,308,184,500 charge on their statements.

...

Josh Muszynski, 22, of Manchester, New Hampshire, was one Visa customer aghast to find the 17-digit charge on his bill. Adding insult to injury, he had also been hit with a $15 overdraft fee.

He noticed that his debt exceeded the world GDP while making a routine balance inquiry on his online Bank of America account. According to his statement, he had spent the profound sum in one pop at a nearby Mobil gas station -- his regular stop for Camel cigarettes.

...

Finally, a bank representative told him that the $23 quadrillion charge -- and the $15 overdraft fee -- would be stricken from his account."

Visa blamed the problem on a "temporary programming error at Visa Debit Processing Services ... [which] caused some transactions to be inaccurately posted to a small number of Visa prepaid accounts."


Five points/questions seem to arise from this story:
1. A $15 dollar overdraft fee for a $23 quadrillion charge seems quite reasonable.
2. How did Visa not pick up that a statement was being produced for a figure some 2,000 times larger than the US national debt?
3. How can any "prepaid" card have any outstanding amount on a statement?
4. How did 13,000 people end up with the same charged figure?
4. Do VISA do any software checking before updating their systems, no really?