Belviana agreed to rent a room for $300 from Belle for 3 days in Collegetown, MT. She planned to spend the weekend in Collegetown attending the big game, and going to the parade before the game, the pep rally, and the tailgate party. One week prior to the big game, the entire team was suspended for violating school policies. The team was forced to forfeit the game and all weekend activities were cancelled. Belviana told Belle that she would no longer need the room and requested a refund of the $300. Belle refused. Belviana sued Belle and won. On what doctrine did the court likely base its decision?