Consider the following:
Orbitz may refuse to deliver Shares to the Employee if Employee fails to comply with Employee’s obligations in connection with the Tax Related Items.
Refusal is in response to a request. Instead of may refuse, I’d always use that standard component of language of discretion, is not required to. It allows you to address the issue on a more fundamental level.
And hey, how about this:
Acme does not expect Orbitz to deliver Shares to the Employee if Employee fails to comply with Employee’s obligations in connection with the Tax Related Items.
You guessed it: Saying that Party A does not expect Party B to take an action is an oblique way of saying that Party B is not required to take that action.
There are endless ways of conveying a given categories-of-contract-language meaning, but one way will make the most sense. Use it consistently.
Three of the several categories of contract language are (a) obligation, (b) discretion, and (c) prohibition.
Whenever you negate one category, be aware that the question is open whether one of the others applies:
(1) Negating an obligation is compatible with the contract’s prohibiting the conduct, authorizing it, or neither. “The Driver is not required to drive faster than 55 mph [but may do so where legal] [and shall not do so where illegal].”
(2) Negating discretion is compatible with the contract’s prohibiting or requiring the conduct, or neither. “Of the three cars on the lot, the Manager may sell 1 and 2 at any time, but not 3 [which he shall sell immediately] [which he shall not sell for 30 days] [over which there is a title dispute].”
(3) Negating prohibition can mean that the conduct is mandatory, discretionary, or neither. “Nothing in this agreement prohibits the Janitor from entering the Base on weekends [to perform his required daily duties] [to restock his supplies at a low-traffic time if he finds it convenient to do so] [final word on admission to Base is up to Base security].”
Sometimes the expectation of relevance will reduce or eliminate what logic permits (“Valet shall not park cars on the lawn closer than 50 feet from the House” — does this give the Valet discretion to park cars on the lawn more than 50 feet from the house? Probably yes), but when it matters, draft to eliminate lack of clarity.