I agree with Alan – you’re misreading the advice. The card and device are different. One’s a card, one’s a phone.
As long as every individual uses a different item to pay with they’ll be fine.
The account that cards/phones happen to be linked to isn’t something that can be checked at the gate line, that all goes on in the backend processing later on so the gate has no way of knowing anything that may link card and phone to the same owner.
