Dean and Bicker, when you speak of paper lists are you talking about the clipboards? Those are used at many maybe all of the restaurants but the podiums do have computer screens. I think the restaurants print out the ARs earlier in the day and somehow use those clipboards to keep track. But they all have the computer screens. Recvently made ARs are on found on the screen.
A couple of other thoughts:
DVC Grandpa noticed empty tables on Thanksgiving and a couple of days later asked about them. It could be that the CM was wrong. But otherwise, it seems likely that people WERE forfeiting deposits because as others have said, on holidays they are required at most restaurants.
His other experience at the All Star Cafe was very different I would bet. In that case, it could very well be that few tables are ever released for ARs but instead held for patrons of the venues.
In my experience, some hotel tables are held for hotel guests. I think they are probably released at some point but I don't know the specifics. I just know when WDW Dining has told me there are no tables available, I have been able to dine.

My point is that what some think is a problem may be just the way WDW handles their tables.