This is a paragraph according to WDW News Today.
"Guests have the option of not putting a credit card on file, but they will be unable to use their Magic Band for charging at the resort or in the parks. As is current practice, guests will be able to visit the front desk to apply cash or gift card payments against their balance due to avoid actual charges being placed on their credit card."
Here's the link. https://wdwnt.com/2019/01/breaking-new-credit-card-charge-policy-for-disney-world-resort-guests-begins-february-27th-2019/