Casualties with an altered mental status due to head injury often act (and react) inappropriately and can be a potential danger to themselves, first responders, and their unit and mission.

First responders and medical personnel must recognize when a casualty has an altered mental status and take steps to disarm the casualty and secure any communication equipment they may be carrying. 

Casualties are likely to resist this but will usually respond to reassurance that you are securing their equipment while you evaluate and care for them and that their unit will take responsibility for it.