Can someone explain how this works?
When you check in, the CM will ask you if you'd like to apply charging privledges to your reservation. You can place it on every room key, or just one, your choice.
Depending on your resort you'll be "pre approved" for a certain amount... for instance when we were at the values, it was $500... at the Grand Floridian... it was $1200. Not sure whether that has to do with the credit card being applied or the resort status... just sharing our personal experience.
Your key will work just like any standard Credit Card. All charges will be monitored and logged and an invoice will be placed on your door the morning of your check out. We usually keep all reciepts to ensure it shows correct charges.
Since you've left CC information, you'll be provided with "express checkout" meaning that you won't have to go to the front desk to "settle" your tab, the amount given on your invoice will be charged to the CC information given on the day of check out.
If you would prefer to pay some of your tab in cash or with a different CC then simply head down to the front desk the night before your leave or any day during during the week, ask for a print out of charges, and let them know how much you'd like to pay and in what form. The front desk CM will print you out a new invoice reflecting the remaining charges, if any.
Are there places that we can't use our keycard in this way? For example the snack carts, are they cash only?
We've found that nearly every snack cart takes room charges with exception to a small few. We usually always ask before we place our order and carry a small amount of cash in the parks just in case.