That's actually a very good question. This should probably be asked on the Q&A. Personally, I would think that in the spirit of the game, a penalty would not be assigned, just because if it does happen, it will likely be accidental, though I would think that they would still count the unscored tube as if it was still there.
That's just my opinion though, you'll have to comb the rules or the Q&A for an official answer though.
Edit: Dang it Lil' Lavery beat me to it!
