Having 100% accurate knowledge that a flight is oversold and by how much, is not particularly helpful on the denied boarding front:

1. Nothing you can do about it anyway, so put it out of your mind and plan on flying as scheduled.

2. Flights are oversold and seats open all the time. Thus, no need to DB to anyone. This is especially true xhubs, where a flight can be oversold by 15 and there are 20 misconnects. Remember, carriers spend a lot of $ modeling this stuff so that in an ideal world the flight goes out with every seat filled and no pax DB.

3. Flights are oversold and people don't show by T-15 all the time. The latecomers lose their seat, they are not due any compensation and all are acommodated.

You can drive yourself crazy on this point, but the fact is that the system really does adjust quite quickly.