User blog comment:Ahalosniper/Something of Small Importance/@comment-59290-20100226211219

You are correct. They are a volunteer unit. But, in order to volunteer for service, you must be selected for training. You can either accept this offer (volunteer) or turn it down (not volunteer). It's like Delta Force's methods. An officer may be selected for training and decide not to go for it. It's completely up to him, and that's how one can be both selected and volunteer.