Interestingly, I got a fraud alert email and phone call from Amex on my personal card, which I had before the 30k promo. When I called to confirm that the charge was an unauthorized charge, the rep recited that my last charge was a charge from the mint. I cringed as she said it (I don't want it to turn into a conversation about coins), but she made no comment and that was that.
Unfortuantely, they insisted that my card was now comprised and wanted to issue me a knew one. Ordinarily this is fine, but I have backordered mint purchases, which this will likely screw up.