Active Duty/Reserve/Guard/ROTC/Veterans
Those study abroad participants who are, or have been, affiliated with U.S. military forces are advised to not travel abroad with such documentation drawing attention to this fact. In the unforeseen case of encountering nefarious activity, these individuals could be put at higher risk as could possibly the entire accompanying group.
To cite the Defense Security Service website (excerpted), one should:
"remove anything that might cause you grief if a terrorist sees it, such as military or reserve documentation or humorous cards like the one that identifies you as an 'Honorary Sheriff.' Make copies of your passport, air tickets, all credit cards you take with you, and any other documents to facilitate reporting loss and replacing them. Some travelers prefer to conceal from casual observers that they are American and carry an American passport. They put a plain cover on their passport (covers available in stationery stores)."