Gittin 55 - Private witness
If one says privately to a witness, "This is a Get for my wife," then tells his wife, "Please accept this document of indebtedness," she is divorced. His words are not to nullify the Get but to avoid the embarrassment of the divorce.
If one steals a beam, builds it into his mansion, and is challenged in court, he has to pay the cost of the beam but does not have to return the beam itself. This decree is to make it easy for the people who repent and want to return the stolen goods.