Yes you are wrong if you are thinking about having charging privileges at the resort or via MB which all charge back to your room folio.
It did / does not now matter if you check-in online or at the front desk. In the past they allowed a float of $500-$2000 based on your resort level before changing the credit / debit card associated with your stay.
This was modified last year to start placing an initial hold of $100 and then as you used your MB or room charging privileges addition holds are placed in increments of $100. If you don't want changing privileges no holds will be made against your credit / debit card.
Dave