That's why I didn't say anything about BANK DEBIT CARDS. Don't have one, wouldn't use it if I had one.
I'm well aware of how gas stations work and frequently see those $1 holds for gas charges. I've never seen a HOLD that was even the amount of the purchase, let alone TWICE the purchase price. And those HOLDs last a day, maybe two. Maybe yours works differently than mine, and if it works like you've described you really should think about changing. I've traveled extensively inside the country and out and have never carried more than 2 cards, one of which is a back up. And I've also never been blocked for any time. And of course never lost a card.
And c'mon that was just a little jab about your sister's issue. Not meant to be too mean spirited. :)