I think it will be a long time before they get rid of cards. There are too many old people in casinos with flip phones, and there seems to be too many problems associated with this. What happens if you forget your phone or it's not charged? I guess they could give you a temporary code/phone or something. Anyways, burner phones are cheap(I even save all my old phones). At least the casino won't be able to confiscate your phones if you get caught. They would probably need a warrant or something and since its not illegal, I'm not sure how they could do that. In the meantime, you could probably brick your phone with the touch of a button on your phone/computer from another location. It might even be harder for them to tell whats going on in the first place.