I found out about "blocks" on credit cards during my trip to Denver. There I was paying for a new windshield, ( see Denver trip report--a disastrous road trip--not for the faint of heart ) when my card came back "declined". Talk about an embarrassing and possible life threatening situation, the new windshield was already installed and Mike (the guy at the register) wasn't much interested in our tale of woe, or how my card being declined "had never happened before" ; luckily I had a second card.
Later I found out from Visa, that hotels (our hotel) and car rentals "routinely" put holds on your credit cards "to ensure sufficient funds will be available" by the time you check out or return your car. Visa policy--All holds must be removed within 72 hours

BTW, those gas station cards-also put holds on your credit cards.


Keep'em flying