In the case of the CSP (or really any Chase personal cards) AU cards are IDENTICAL to primary cards. There is literally no difference, and they would have no way of telling which card was used for any specific transaction. Now, if it is true that the transaction needed to occur using the login of the primary cardholder within the Chase Travel, I suppose they could tell that. But even that is weird because Chase Travel requires you to enter your card information in order to process the transaction - which again, is identical. This is why we wouldn't use The Edit credit for the first half of 2025 with the new CSR - you have to have the physical card to use Chase Travel.