bc2000, you have good intents, but I don't think this will work the way you think it will.
Perhaps I misunderstand, but are you suggesting that players who go into CD should be punished on top of losing all the points they bet?
figle already mentioned that even if such a penalty were in place, it would have to be proportional to the pot. This is quite obvious in my mind, because a fixed penalty will have varying degrees of effectiveness among different games. Richer players would be punished to a far lesser degree to newer ones.
What is the point of a negative score? If one can simply reset after the game has finished, going all in would mean that no real consequences are dished out for missing a phase anyways. If there was no reset, then that player would be doomed to never play again, and would simply create a new account.
As well, you already accept that players with a low score are the ones that skip turns. What is the use then, to further lower their score? A player that misses a turn already suffers. If you think it messed up your game, it probably messed up theirs even more. If they go into CD, they lose all the points they invested, and as this is scaled to the pot, it means that they have much more to lose in a higher stakes game where players care more about the game's quality. I think that's an important aspect that your penalty doesn't take into account.
If you have a penalty for CD, you should not excuse those who hit a CD button, who are removed immediately, because they still affect the game greatly, because there is a large risk that you will not find a replacement in time to save any tarnishing of the game.
Anyways, the current point system already has a natural implementation against inactivity, and no further penalty is really needed. Especially not in the form that has been put forward.