This could be fixed by now but I ran into an issue in Dec where all the charges that were made, even when each person in our room res had their own card info under their portfolio, were showing up under the head of the reservation. The front desk knew about the issue and asked us to come back every few days to get the charges sorted out if we continued to charge using MBs. Even though the charges were showing up under one portfolio they had each of our names next to every charge so it was easy for them to transfer the charges over to the right portfolio. It took maybe 5-10mins every other day after getting back from the parks to sort it out. The cards under each person's portfolio don't actually get charged until checkout or after every $500 spent so if you keep in mind the charges you make throughout the day there shouldn't an issue. Of course, it might just be more convenient and easier to use your cards.