I was declined using my Discover card the other day for $1400. When I called the CSR said the store was not reading the CSV number correctly and suggested doing the transaction manually. This also failed. I called again and this time the CSR said Discover had declined because of suspected fraud. After proving I was me they authorized the charge. A great inconvenience to me. But NOW IT GETS INTERESTING. I called to learn why this happened and was told that a number of account numbers were compromised in January 2009 and those accounts were marked for hightened security. They recommended that I cancel my card and they would issue a new card. Of course lots of folks out there are marked for this additional security, don't know about it, could get declined and not be able to resolve the issue as quickly as I did.