In the ketuba, the ק in the word "וקנינא" is sometimes left incomplete until the time that the ketuba is signed. Why is the ketuba left incomplete?
The Aruch Hashulchan writes that one is allowed to write spare contracts. He says that we don't say that it looks like a lie (the scribe writes that someone borrowed money before it happened) unless there are witnesses signed there.
However, he says that some say not to write the last part of the contract (the Toref). This is usually taken care of by not writing "VeKinyana".