The Opera is responsible for developing the legal difference between a condition and a warranty in a contract. Breaching a warranty allows a claim for damages only. Breaching a condition allows a party to terminate a contract and also claim damages.
Two important cases involved Opera singers and both were heard by Blackburn J in 1876. Bettini & Gye (1876) 1 QBD 183 is foundational for warranties and Poussard v Spiers and Pond (1876) 1 QBD 410 establishes the law around conditions.
The messages in those very old cases still holds true for entertainers today. If a performer is contracted to specifically do something and does not, the court will likely see that as a breach of condition and allow the contract can be terminated.
In the Bettini case, Mr Bettini did not arrive on time for rehearsals 6 days before the performance as contracted. The court said that being late was not fundamental to the heart of the contract to perform. Mr Gye could only claim damages for any losses incurred such as lost rehearsal costs or time but could not end the contract with Mr Bettini.
Compare that to the Poussard case where Mde Poussard was contracted to perform on opening night, but could not due to illness. The obligation to perform on opening night was so fundamental – it was at the root (or heart) of the contract that to not perform was a breach – even in light of the illness!
In this day and age these types of cases are rare as entertainers and producers & managers rely on ‘relationships’ to hold things together. That’s OK, but so you don’t damage relationships, understand what you’re getting yourself into.
Entertainers should know the heart of their obligations and be prepared to carry them out. As for producers & managers, if an obligation on an entertainer is so important that you would end the contract if they didn’t perform it – then say so in the contract.