Soldiers stupid and disobedient enough to carry their own tracking devices into the field on operations are teaching their units harsh lessons when entering combat. The Association of the United States Army, the U.S. Army's professional association and lobbying group, has an article on how mobile phones are used against soldiers carrying them in the field [ausa.org]. This includes, but is not limited to, psychological operations, artillery strikes, monitoring, or all three at once. Given the lax discipline about leaving the mobile phones behind, the attacks built on phone info have been increasingly successful [businessinsider.com] both physically and mentally.