Having a cell phone isn't going to help even a little bit if there's an active shooter at a school. The only thing a kid should be doing in that situation is hiding, or escaping if it's safe to do so. Likely it'll make things worse... some kid will get a loud notification on their phone, which will give away their location to the shooter.

The predator example sounds pretty flimsy and unlikely to me as well.

Honestly, your reaction to this just seems to follow the fear-based rationales that people put forth for a lot of things, when the fears are overblown or the risks are low.