A valid offer may be in the form of an act for a promise, which is an offer to enter into
an inverted unilateral contract.
Revised Article 3 provides that the impostor rule does not include an impostor who
impersonates an agent of a principal and who induces someone to create a negotiable
instrument payable to the principal.
Ann, in the presence of Betty, tells Thomas that Ann is Betty’s agent. In reality, Ann had
no authority. Betty hears the statement, but she says nothing. In reliance, Thomas ships
goods to Betty on Ann’s order. Betty is liable even though no actual authority existed.
Charitable subscriptions are one of the most frequently occurring applications of the
doctrine of promissory estoppel.