About an hour ago I to book a flight with American Airlines (UK site, and charged in GBP) but the card kept declining. When I called up to enquire why, they said that as a result of recent fraud they have blocked all transactions processed by American companies on the Amex card that involve some sort of "tester payment," in response to the fraud this thread refers to. The guy told me that my Mastercard would work fine, but I decided to use my (non-Lloyds) Amex card. He also mentioned that he had dealt with customers in the past few weeks that have been blocked by a number of USA websites that put through these small "tester payments" (his words not mine) including the USA Amazon site. Apparently this is a temporary measure (I hope so, as I'm off to the states next summer!) but he couldn't give me any sort of indication as to how long it would last.

I had my card declined two weeks ago, in a number of different shops, but had no communications to advise me of this. When I called them they sent me a replacement card and advised that someone tried to do an online transaction for 77p with Braintree Payments. The payment never went through and didn't appear on my statement, so I didn't have to ask for a refund.