Had They Never Cut Over A System Before
I suspect that anyone who has ever cut over a system or been remotely involved with a cut over of a system would have been aware that testing is absolutely vital. Not only that but testing the assumptions on which forecasts were built is essential. The stimulus of a new system upon customer demand for services is very often woefully forecast or understood. The only good thing in this case, was that those customers who set out to see what breaks, were spoilt for choice; they did not know that the system was already broken and untested in so many areas that they were bound to have some fun.
So the fraudsters had a party time.
Many years ago I tested what would happen when the demand rush really started. I simulated the effect and listened to fuses blow. When working with a supplier I questioned some 'example data', believing it was for demonstration purposes. Sadly, it was real planning data from an unnamed customer. I predicted the go live failure. Their customer had forecast less than 10% of the actual user impact; ouch.