Jon Favreau explains the reasoning behind giving out challenge coins for Cowboys & Aliens and Iron Man 2:
“…in the military, when we would work with the Air Force a lot, on ‘Iron Man,’ ‘Iron Man 2′, we were at Edwards Air Force Base. And I would shake hands with people, and I would feel they would stick a coin in my hands, right? And it was a challenge coin. The reason they call it challenge coins is, if you don’t have your unit coin, or a unit coin with you when you’re out drinking, and somebody pulls your glass at the bar, if anybody in the bar doesn’t have a coin, they have to buy a round for everybody. But if you challenge everybody and everybody has it, you have to buy the round for everybody. But it was also a sign of respect, that they liked the way the crew was, and the way we treated, you know, them, and who were – you know, are developed a nice relationship with any of the individuals – it was a sign of respect to give a coin. So I had them made up for “Ironman II”. And it became like a tradition. So I had them made up for ‘Cowboys and Aliens’ also. I made them look a little more old school.”
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