No they won't. They will take one credit card as the one for establishing the room charges. You will have a "credit limit" depending on what resort you are staying at - $500 @ value resorts, $1000 @ moderates, or $1500 @ deluxe & home away from home. Nothing will be charged to the credit card until that limit is reached.
You can keep track of who charges what yourself. Go down to the front desk each night and request a statement. Next to each transaction you will see either an 01, 02, 03, or 04. This corresponds to the number on each resort ID. Just add up what card #01 charged, what card #2 charged, etc.
Then, the night before you are leaving, bring everyone down to the front desk and you put whatever dollar amount you figured each person owes on their individual credit card. If you do not do this the night before leaving, the entire charge will be put through on the card that was presented at check in.
