You may remember a case from several years ago where a student of Arabic was detained by the TSA because he had Arabic flash cards. He was studying Arabic. Flash cards can actually be useful in studying a language.
Arabic is the fifth-most-commonly-spoken language on the planet Earth. It is the official language of 27 nations. Most importantly, it is language, not a weapon. If flashcards are dangerous, they are equally dangerous no matter what is written on them. What could a passenger do with Arabic on flashcards that he couldn’t do without the flash cards?
See my previous post, How Arabic is Like Parseltongue. https://snarla.wordpress.com/2009/06/27/how-arabic-is-like-parseltongue/
Here’s the recent news story at Raw Story: http://www.rawstory.com/rs/2013/12/25/federal-judge-rules-that-tsa-fbi-can-detain-and-arrest-you-for-carrying-arabic-flashcards/
Observe the fool-proof logic:
TSA AGENT: Do you know who did 9/11?
GEORGE: Osama bin Laden.
TSA AGENT: Do you know what language he spoke?
TSA AGENT: Do you see why these cards are suspicious?