Athletics: When a high school senior decides on which college he or she would like to attend and receive an athletic scholarship to do so, a letter of intent is signed. Many sports even have a national signing day to keep the playing field level.
For example, I usually buy houses directly from sellers, but last week I started to make some creative owner financing offers for some houses through real estate agents. Once I was able to talk to the agents representing me, they immediately saw the benefits of my offer to some sellers. Unfortunately, the agents I talked to would be presenting my offer to another agent that represented the seller.