Just did a cash ressie for a Friday night in the middle of our trip, and it's just as Debbi B and Ralph&Pam have said. Member's Services took my credit card #, but the card was not charged until I checked in. There was a 5 day cancellation policy.
I was guaranteed that I would not have to change rooms, and my various reservations were all linked together. Also did NOT have to check in/out again.
I was told several times that if I booked through CRO they would note that and try to keep me in the same room, but would not guarantee it. Also, would need to stand in line and check in/out. CRO also needs to make a note on that reservation to connect it to the points reservations.
I decided to pay $20 more for the night (than the AP rate), with a Member's Discount and not have any hassle with worrying about switching rooms. Since our cash stay was in the middle, it would have meant checking in/out twice and having to worry two times about possibly moving. Others have posted that they had an AP ressie and were lucky and didn't have to move.