This is sort of on topic since this thread seems to be a good discussion of contractual language...
As far as our contract is concerned, what is the legal meaning of the word "Shall". It's all over our contract, and my assumption would be that "shall" means "will" and implies an obligation. As opposed to "may" which implies there might be other options.
An example in our CBA would be: "4.H.1. A pilot who is assigned a trip(s) or base standby in reserve status shall have the trip guarantee or standby pay credited toward his leveling and/or RLG as follows:"
Does that "shall" obligate the company to provide a pilot what is described in that section?