Which is really the question of what authority will police use to question or detain people.

Now, there is nothing in the law that prohibits police officers from questioning people.

However, an officer's right to demand identification in this circumstance is far less certain, despite the widespread over-interpretation of the recent Hiibel Supreme Court case.

(The Supremes carefully worded that decision so that police in some states can require a person to identify themselves if the police have a reasonable suspicion that a crime has or is about to happen, but its unclear whether a second-hand hunch is reason enough, or even that was enough, whether one could simply state one's name as a form of identificatiion.)

So the question is, if a passenger is 'referred' to an officer, would they 1) have to show identification or 2) answer the questions. Also unclear is what a police officer could do if a person refused to do either.

Remember that a person always has the right to refuse to answer a police officer's questions.

Police may not be detain you for not answering a question, unless they arrest you and charge you with a crime.

But, airports are not city streets. And, the law gives the TSA wide latitude to search passengers belongings.

The TSA also has a policy of requiring airlines to ask passengers for identification, upon pain of an intensive search.

Though government lawyers refuse to acknowledge that that policy exists, everybody knows it does.

Hell, both the TSA and the Department of Transportation have both admitted as much in the Federal Register this summer.

But the same government lawyers also argue that the identification-or-search requirement can not be challenged since it is a "law enforcement technique" designed to prevent terrorism and hijackings.

Would the same argument apply to local police officers working in an airport?

If a police officer questions a passenger, and does not like their answers or encounters a person who won't answer the questions, what are they to do?

Can they themselves prevent the passenger from proceeding to their plane?

Can they tell a screener not to let the person board?

If so, what authority are either of them invoking?

Airline travel may not be a right, but airlines are still common carriers, who have to transport a passenger unless the captain refuses the passenger or the passenger refuses to comply with a security rule.

But does the TSA or law enforcement have the right to ground a passenger who is not on a watchlist and does not have any prohibited items, on the grounds that the person won't answer questions or admits to travelling often to Pakistan?

My hunch is no, the airport exception does not reach that far.

But given the government's filings in the Gilmore v. Ashcroft case, I think that Justice Department lawyers would likely say 'Yes, they do' and 'No, you can not see the reason why or challenge it in court.'