Theoretically, it's percentage of completion of games. If you didn't complete a game, whether by quitting or forfeiting or through no fault of your own (your system or connection, for instance), this should reflect in your percentage. Delaying the game for 5 to 15 minutes for the remaining players is a pain in the butt, whether it's intentional or equipment related.
On the other hand, no penalty should be assessed if the disconnection is WGT's fault, and no penalty should be assessed against the partner of the one who disconnected. No penalty should be assessed against the waiters if WGT eventually cancels participation, whatever the reason.
It's a good idea. WGT has yet to implement it properly and fairly.
Frankly, I don't want to play with a person having disconnection problems, even if they never quit on purpose. I will like the feature if it ever works properly. In the meantime, I avoid multiplayer games unless there are credits involved.