How much does the replicator generally de-replicate when processing a meal?
We have seen glasses full of beverages replicated in a single cloud of sparks. Air would need to be pushed aside for that, but nothing more, and not particularly carefully at that. Replicating the drink after the vessel would call for finesse so that air bubbles don't cause problems, though. And if somebody adjusts her order after the delivery process has already begun, does the replicator start anew, or does it add the parsley as needed, and swap the carrots for the fries?
The ability to remove stuff would seem to come in awfully handy in the most routine of cases already. And the replicator does do the dishes. If you add a toothpick on your table, or there's a bit of extra saliva there, it wouldn't do for the replicator to refuse to erase those.
Then again, the AI controlling the everyday doodads of Trek is pretty clever. It handles the sliding doors very well, it connects the calls without a hitch. It probably could be trusted to make sure the replicator removes all the extra dirt your five-year-old left on the plate, but not his greasy little fingers.
Timo Saloniemi