What can be done is to book additional nights to one real stay - e.g. book one day prior to planned arrival and one night after planned departure (cool if you have a cheap 5000 bonus points rate) - to get two extra nights. you should inform the hotel that you arrive late so the reservation doesn't get cancelled.
I only do this when I have an early morning arrival (to secure a room ready for me) and when I have a late departure (after regular checkout time).