The answer depends on if you are using the dining plan or not and depending on your tier....
Tier 1 is credit card payment in full at time of reservation...Unless you are willing to do the 9:30 show...In that case you can use the 2 credits from the dining plan...And then they require the credit card # to hold your seats...If you are not on the plan you can still reserve with credit card and pay when you arrive...
Tier 2 and 3 you can pay at time of reservation OR you can give a credit card to hold your seats...Many people use the 2 credits to see the 5:00 or 7:15 show...
You get a full refund ff you pay cash or will not get charged if give the credit card to hold your reservation ONLY IF you can cancel 48 hours prior.