Originally Posted by HarryT
Probably because the same card had previously been associated with a different account. Whether you appreciate it or not, these checks are there for your protection.
Indeed. Two years ago I was called by Visa directly.
They told me they were alerted by "an unexpected purshasing pattern". So, they explained that their computer system generated an alert because I used my credit card to buy for about $500 of stuff in several countries. Normally, my credit card was used for some Android apps costing $1 or so a piece, some sheet music costing $2, and the biggest purshase was a bunch of second hand CD's at Amazon for $15 or so.
Visa wanted to know: Have you still got your credit card? Did you really buy stuff for $500 in 4 countries? Should we block these purchases? After telling them "Yes, yes", and "no", and mentioning what they should be seeing over there (which was indeed correct), they wished me a nice evening, and never called afterward.
Having no experience with this, it was a bit of a "Huh?" moment, but afterward, I can definitely appreciate it. And yes, I would want and even expect Amazon to contact me if my credit card suddenly shows up in another account.