Unless Miller and his party got to the airport 3 hours earlier than their flight (entirely possible, even likely), why were they detained for 3 hours if they had nothing to say? How long does it take to say, "We have nothing to say"?
I agree - lefty intimidation tactics.
I've read over and over and over again, especially in the U.S., NEVER answer any questions from LEOs. Even the so-called "harmless" questions like, "where ya goin'?" or "Can I look inside your vehicle?"