Are you sure they aren't legally binding? If they form part of the terms and conditions for the crew then they are a legal contract between the company and the employee, enforcable in a court of law! Since a scheduling agreement also requires approval from the CAA it is also enforcable through them, and they are also within their rights to audit rosters based on the scheduling agreement as well as CAP371. If a crew has operated outside of the agreement (but within CAP371) without their approval it would be deemed a non-conformity. I must confess though I have never heard of the CAA auditing scheduling agreements, but that doesn't mean they won't!