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.