You can set up a room charge with a credit card, debit card (with VISA/MC logo), travelers checks, cash, even Disney Dollars.
The aforementioned limits by level of resort are UPPER limits. If you are staying at a Moderate, you don't have to set up a room charge with a $1,000 limit ... you can set it up for $752.09 if you really want to.
If you backed up the room charge with credit or debit card, when you reach/exceed your limit your credit/debit card will be charged IMMEDIATELY and AUTOMATICALLY. At that point, if you want further room charge privileges you have to contact your resort's front desk. You can do this by phone.
Let's say you set up a $500 room charge and had a $495 balance on it. You are in Magic Kingdom and go to charge a $12 souvenir and your room charge will be declined because it's over the limit. The resort just charged your credit/debit card for the $495. You can stand there right there and call your resort's front desk from your cellphone. You can then give verbal authorization to set up another room charge using the same credit/debit card. It can be for any amount (within the pre-set limit), it doesn't have to be for the identical amount you set the first one up for.
Before you reach your limit, you are free to go to the front desk and pay off the account using any OTHER means. For example, let's say you brought a bunch of travelers checks with you and you want to use them before you go back home. Rather than having the room charge balance be charged to your credit card, you can pay it off with the travelers checks instead, if you want. But again, this must be before you reach your limit, before the amount actually does get charged to your card.
I researched this before my last trip. It worked exactly as described -- it took me about 90 seconds to set up the next room charge by cellphone. The only problem was that I had to convince the front desk CM that she could set up a room charge for LESS than POFQ's pre-set maximum limit of $1,000. She said she wasn't allowed to, I told her I'd done it many times, including the room charge for $800 that just got charged to my debit card because it had just reached its $800 limit! I think she needed to ask a manager, but obviously she learned something new that day.
But I repeat ... if you present plastic at the front desk to set up a room charge,
THEY DO NOT PLACE A HOLD ON THAT ACCOUNT. But you don't have to trust me ... call your resort and ask them yourself!