If a party obtains a preliminary injunction, it does not become effective until that party posts a bond. This requirement is set forth in section 529 of the Code of Civil Procedure. The purpose of the bond requirement is to make sure that if damages are suffered while an injunction is in place, compensation will be available to the injured party if and when the injunction is lifted.
But can the bond requirement be waived by a party who fails to object? Yes. The court of appeal concluded that the bond requirement can be waived. The court relied on section 3513 of the Civil Code, which provides that “Anyone may waive the advantage of a law intended solely for his benefit.”
The case on this point is
Smith v. Adventist Health System/West. A copy is attached.