1) everyone sees you're wearing them, meaning they can prepare.
2) knife from alarm down solves the problem is seconds.
3) alarm might be nice, but let's be honest. Would you feel brave enough to run into 5 piece priests to safe her?
4) even if it sent a call directly to cops including your location... When seconds are what matters, cops are mere minutes away.
GUN...1 gun solves it all.
BTW... was this made by one of these "woman inventors" everyone keeps talking about?