Here are my three simple rules of self-defense. They can be applied without any self-defense training, only using a little common sense:

1. Avoid places and situations where you need to defend yourself
2. Move away from places and situations where you need to defend yourself, run if necessary
3. If someone surprise attacks you, parry/break free using whatever technique you have at your disposal (hit them with your umbrella!), then see rule 2.

If you feel this limits your freedom, use your vote to change the situation, not your life!