In today's increasingly dangerous world one has to be prepared for all sorts of contigencies. We have a choice. We can either live in fear or we can take control of our own destinies. While law enforcement personnel do a fine job protecting our citizens, they cannot be in all places at all times. Much like our pilgrim and pioneer ancestors, we have a certain responsibility to protect and defend ourselves.
This isn't hard to do. It's quite simple really. Something as simple as a whistle could save your life.
A loud, shrill noise has the potential to scare off assailants as well as alerting others around you to the fact that you're in danger.
Pepper sprays are also a non-violent means of self-defense.
Of course the best protection is to avoid risky areas and situations in the first place, but caution can only take us so far. It never hurts to have some back up.