In the current social and legal climate, proving and executing the wills of individuals is extremely complex and the subject of much litigation. That is so, even when all of the terms and wishes of the maker of the will are on the face of the document itself. As far as the law is concerned, mayhem then ensues when there is a promise or other term that is asserted by another party, and that term or promise is not on the document itself.
The most obvious example of this is where the wills of two or more people are made in contemplation of each other’s will. Reserved in general for relationships of a domestic nature, this concept has evolved over hundreds of years.