Originally Posted by SailorJerry

I think if you look at any contract you have to take it from a very fundamental level. No MAY no SHALL no TO THE EXTENT POSSIBLE. Only the company WILL and the pilot WILL.

Even though a law dictionary finds SHALL to be imperative it's not as concrete as WILL. I figure it's easier to get a clear intent through negotiations and a good Contract Administrator can easily add "Or Else" to the end.