You don't "have to", but they can deport you and refuse entry in the future in retaliation. It's a variant of the TSA not being able to "compel" you to a search, but they can refuse you from flying.

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two_handfuls 26 minutes ago | parent | next [-]

The question was: "Does that apply to non-citizens?"

Saying "they can deport you" without specifying whether the hypothetical "you" is a citizen or not means you did not answer the question.

Not that you have to answer a stranger's question, but I thought I would clear the confusion in the hope it may be helpful.

	▲	gruez 17 minutes ago \| parent [-]
		The premise (non-citizen) is in the question and doesn't need to be repeated. C'mon, this isn't grade school where you have to answer questions by first restating the question in its entirety.

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DANmode 27 minutes ago | parent | prev | next [-]

They can lie, and pretend you’re uncooperative,

or that their investigation took longer than the duration until your intended flight,

but, no, they can’t legally refuse you from flying without cause or suspicion.

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43 minutes ago | parent | prev [-]

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