Well, the store doesn't perform the authorisation, the bank does. And there are pretty strict legal requirements for the anti-fraud systems. Not sure they could actually do what you're suggesting (the bank would probably squarely refuse).
It is also entirely possible that the bank's auth system was at fault there. A, erm, friend of mine told me it kinda happened recently at the bank they are working with (not in the UK).
Biting the hand that feeds IT
