Pagers are not used in the teen program (as of Feb, 2004 cruise). Teens are thought to be old enough to be responsible for themselves. However, if you have a teen AND a younger child, you will still be issued a pager and your teen can stop by the club or lab and ask to have you paged if needed.
There is no sign in/out system for teens...again, they are considered old enough to be on their own. I was totally comfortable with my DD in The Stack (I did go meet the counsellors on the first day). She turned 13 on the cruise, and absolutely LOVED The Stack. However...as to comfort....this was our 10th cruise on The Magic, so we feel that she practically grew up on the ship. It's the only vacation she wants!
The pagers are free while on the ship, but you sign an agreement that you will be billed $150 if you fail to return it. Replacement batteries are free if needed.