I work in the back office on graveyard at the Contemporary. If you don't have express checkout turned on it won't be charged automatically; you could have asked to have it turned off, or a cast member could have turned it off if he thought there was a chance something might be wrong on the charges (often, for example, if there are multiple people charging to different folios) and you would want to see the final bill before paying, or the charge could have failed while the express checkout batch was running (happens a couple times a night to a handful of reservations, just a side effect of putting thousands of charges through at the same time). In any case, the cast member you checked out with should have taken payment once you approved that everything was right, but they could have just forgotten for some reason or our property management system could have been going through a period when charging wasn't working which happens for brief periods most mornings. Every couple hours as the day goes on checked out reservations are checked to see if they have a balance and payment is manually taken (mostly because people can still charge to the room until midnight after they check out, but also for situations when payment wasn't taken in the morning for one of the reasons above.) Or, as has been mentioned, it could be some hitch with the system between the hotel and the bank. As long as all the charges are ones you actually made and you were not double charged I wouldn't worry about it. There is a number on the bottom of your folio you can call to talk to research and billing if there are any mistakes or you have any questions about the folio.
-Harry