For something that has been the subject of so much discussion it sure seems like there is so much confusion about this. FWIW, here is what happened to me last week for travel to DUS:

Did OLCI but then found out I could leave earlier so I had them remove the checkin so I could look for FlyNow/Standby the next morning. Next morning nothing available so I go to check in again only to find that my exit row on TATL leg is gone. Apparently, when I was unchecked, the system took away my seat assignments and randomly reassigned me. Now all exit rows full so I'm screwed. Fortunately, supervisor at gate was able to move a Plat to WBC and then gave me back my exit seat.

I would imagine that had I not checked in at all, had I just cancelled during OLCI before getting to the last two steps, this probably would not have happened. But it is obvious that there are still glitches in the system and until a better product is put in place it sounds like you still need to play the shell game.

It sure would be nice to get this settled and then all of these threads can be closed and archived.