Had a HIX stay in Tampa earlier this year where I booked with one card, but then got a new card where I was trying to hit a sign-up spend bonus. Gave them the new card at check-in, and they charged the first card used for the reservation anyways, and since they were both AmExes, I didn't notice until statement closing. Annoying, but fortunately I hadn't cut it too close and still got my sign-up bonus with lots of room to spare.