“Equitable estoppel, traditionally known as estoppel in pais, is a defensive doctrine operating to prevent one party from taking an unfair advantage of another. The doctrine is founded on concepts of equity, conscience, and fair dealing. The essence of an estoppel is that, through false language or conduct, the person to be estopped has caused another to act in a way that person would not otherwise have acted and has caused injury as a result. Founded in equity, estoppel rests on the totality of the circumstances rather than any inflexible rule of law. Despite its equitable origins, the doctrine of estoppel is applicable in actions at law as well as in equity and in administrative proceedings.”
[California Affirmative Defenses [certain citations omitted]]
