Don't think that it's a personal thing - it could be something as simple as the card being tied to one country but the registration address being another.
It could also be that it was an odd friday and that you hit the enter key left handed.
Fraud detection is like that. One thing to know is that DH doesn't play when it comes to bans. if you're banned, there's NO appeal. There are plenty of other hosting companies to go with that don't completely suck.
I could have recommended Lunar Pages (lunarpages.com) in the past, but recently they got a little evil. You could try siteground.com also. Neither are DH, but you can still get your site up and out there for not too much cash.
Wholly - Use promo code WhollyMindless for full 97$ credit. Let me know if you want something else!