A staffing company wants you to agree to give a 15 or 30 day notice before you voluntarily leave. But they have to give you no notice. One attorney said that in that business model, this is common. Another attorney says that it is not unreasonable to ask for this clause to be reciprocal. You do not think that the company will agree to making it reciprocal. Is it possible for the project owner to give a contractor advance notice that the contract will end sooner than expected?
Yes. Ask for the clause to be reciprocal or ask for the clause to be removed. If you are constructively terminated in certain jurisdictions, quitting without notice is acceptable. Some staffing companies will either remove the clause or make the notice reciprocal. You should always ask for the staffing company to provide notice as soon as they hear from the client that your contract will end. Even if they won't concede to the notice in the contract, they will likely tell you via email (during this negotiation phase) that they will let you know as soon as possible. Ideally it will be in the contract. But sudden terminations can happen even when there is no indication from the interviewer or staffing company that they would do such a thing. This way a sudden termination may be less sudden. It can be easier to secure employment when you have a job.
You may or may not want to insist that the "as much notice as possible" clause is in the contract. Many contracts have an "entire agreement" clause which says if the agreement between the parties is not in the contract, it is probably not enforceable. Emails can form a basis of fraudulent attempt by one party to induce you to signing a contract, but this collateral evidence may or may not withstand the "entire agreement" clause. In other words such pre-execution-of-the-contract emails may not be enforceable if a subsequent contract was signed with an "entire agreement" clause, but those emails could still provide some assistance to you in a legal proceeding. You never know when an end client may want to the end the contract, but the staffing company does not think you will need to know right away that your work is ending. If you express your interest in learning right away that it is ending, they may fit protective language into the contract to give you a right to know immediately. The end client may share with you their advance notice to the staffing company. Some staffing companies will pay you for the notice period without having you work for any end client if the clause is in the contract.