Contributor Dugan Barr writes today (Sunday):
My daughter Catie missed a plane from France to Spain, so she needed to get a ticket on another airline.  The airline would not accept a Visa from Bank of America or a Mastercard from Chase.  Both accounts are current and nowhere near their limits.  The airline told Catie that their claims were not getting processed by the banks, so they would not accept them.  They did accept American Express.  Pretty scary.