With security being at a higher level due to terrorist activities many airports have various security groups which ensure the security and safety of airline personnel and employees.  Within the United States we have the TSA, Transportation Security Administration.  These men and women inspect liteally thousands of personnel and luggage on a daily basis.  While traveling, one of my bags was tagged which meant it required additional inspection.  The reason it was tagged was because my bag had training weapons such as wooden and rubber knives and guns which I use during some of my Ho Sin Sul workshops/clinics/seminars. 
 
One of the TSA personnel started questioning me about the items and I replied to him that I was a Taekwon-Do student/instructor going to visit my instructor and do a seminar on weapon defense.  The TSA gentleman asked me if I had any proof or some type of creditential basically stating that I was a martial arts instructor.  At that point, I pulled out my ITF Black Belt Status Card.  Once the TSA personnel saw it they simply thanked me and let my bags through.
 
Another time a black belt status card assisted me was when I deployed to Iraq, Saudia Arabia and Kuwait.  I desired to operate small clubs on base utilizing military facilities.  All of the folks I had to talk with required me to show some documentation of my rank and/or credentials for me to be qualified to teach these programs.  Again, I showed them my black belt status card and that to them was all they needed to see. 
 
In all, the ITF black belt status card is required for national and international competitions and events.  However, they have come in handy on several other occasions as well for this Taekwon-Do student/instructor.