this practice is why we always take at minimum a second card but generally a 3rd credit card with us b/c disney gaffed BIG TIME with us on a trip and didn't drop the holds so it ended up (not actual numbers but gives the idea)-
day 1 charged for remaining balance on room/parking...added incidental $100 hold, we spent $100, disney processed $100, posted another $100 hold BUT did not drop room/parking hold...or day 1 incidental hold so...
day 2 original room/parking hold still sitting there plus now a $200 hold (original $100 + new $100), we spent $100, they processed/posted another (again dropping none of the others)
day 3 original room/parking hold plus $300 hold (original, day before, new day), we spent $100....
by day 10 of a 12 day stay we got an alert that our credit card (high limit) was maxed out (this was on a late friday afternoon-we had a sunday checkout). we called the credit card company fearing fraud and they detailed all of disney's holds/charges (all of room/parking charges PLUS the full hold for the charges, all of the daily charges PLUS $6000 plus in accumulated holds). we went to front desk and inquired, credit card company offered to facilitate a phone conversation to explain the issue to resort. front desk manager acknowledged it looked like an error on disney's part, credit card company explained how to resolve BUT front desk manager said that had to be handled by a different offsite accounting division which was only open 9-5 m-f, not open on weekends and we would have to resolve it the following week ('oh, and btw-it can take 7-10 work days for the posting correction to show' says front desk manager who is also saying we need to provide a new card or find another means to pay for incidentals).
we ended up with close to $20K in unreleased holds that took a couple of weeks to resolve (disney aknowledged their error but not so much as an apology for the inconvenience and stress, had to scramble to find a means to pay for the remainder of our disney vacation let alone our subsequent lodging and meals for travel home.