I've actually had a suite room taken away from me after I physically checked-in. It was at a Courtyard in Tulsa, OK. I arrived around lunch-time and since room was ready they checked me in early to a King suite room. But I had a lunch meeting, so I didn't go up to the room (i.e. I never used my card to open the door.) It seems their system at the time didn't actually "register" me as in the room since I hadn't used my key-card. When I came back later that evening, my key-card didn't work. It seems their system didn't show me as actually checked-in yet. And my room had been given to someone else as an upgrade and of course that person had actually opened the door with their key. Since there were no other King suites available, I didn't get one for that trip.

And now after check-in I always go up and use my key card to get into the room at least once, just in case...