I would take silver or gold coins for barter. If I was abroad, I would take more than I usually do.
I have this:
http://www.specialforces.com/rigger-s-sere-belt

It is a part of my EDC. I typically have some 90% silver coins and a couple quarter eagles in it at all times. Just in case I am in a bind I can hopefully barter my way to more favorable conditions.
I would probably carry the silver coins in a manner that it looks like regular change, and put them in the belt after you are out of the airport because that would look like you are smuggling something. LOL
I also carry a thumb drive with a scan of ALL my Vital documents... DL, birth cert, marriage cert divorce decree, in this belt. It might help in identification if you find yourself suddenly without a wallet.