Walt Disney World announced a new credit card authorization policy today that goes into effect February 27th, 2019. This policy is said to be more in line with the hotel industry.

Under this new policy, Disney Resorts will be putting incremental holds on the credit card for estimated expenses.

Guest staying at Disney Resorts will continue to have the option of not placing a credit card on file, however they will not be able to charge to their room or MagicBand.

Upon checkin guests will be charged the balance of their room stay if not paid in full plus $100. When they reach the $100 in charges to the room account, an additional $100 will be charged.

The ultimate goal of this is to prevent large bills upon checkout that can be denied by the credit card company for a multitude of reasons. 
Guests will continue to be able to pay their balance in cash at all Disney Resorts.
In many ways this can be seen as a good thing as you are not left with an extremely high bill at the end of your trip.