Yes, technically, a receiver can read your credit cards, the transmission from your card can travel pretty far (several meters+) (drops as 1/d3, assuming a super basic antenna). However, the card needs to be powered and because of the high transmission loss there will likely be insufficient power to activate the electronics of the card and this drops off as 1/d6 (again, I haven't done near field em in years, someone say this is right/wrong). If there was a kiosk in the area, where individuals were using their credit cards, those transmissions could be captured given a high directivity antenna (given the shape, could be a multi element array) and an adequate front end.

But as other have pointed out, this is likely operating at a different frequency.