This was my worry. I've had experiences on a few sites (notably, RyanAir always seems to have problems) where I may try 3-4 cards, sometimes multiple times, be

This was my worry. I've had experiences on a few sites (notably, RyanAir always seems to have problems) where I may try 3-4 cards, sometimes multiple times, before the transaction goes through. Note that I have a few US credit cards, plus bank accounts in several countries & currencies... they're all in my name, but I wouldn't be amazed if I triggered some company's automated fraud triggers simply because of that. If they hellbanned my purchases, I'd be seriously pissed... though I totally understand the OPs reasons. I think as long as this has human review I'm in favor -- but if not, that's risking being seriously cruel to a legit user who simply has a non-normal interaction for unpredictable reasons.