Martial arts has rules and regulations and will condition you. There are a few martial arts that will teach you to disarm someone using a gun or knife, but you are better complying with the mugger. The money can be replaced and isn't worth your life or putting someone else's life at risk.

Energizer or Duracell?

I don't see how this is relevant. Just because you know how to fight doesn't mean you have courage, nor does it mean it's always the smart thing to do. Though George St. Pierre is arguably the greatest fighter of our time, I'm fairly confident he is not bullet proof.

What a rip off!!

If you only took karate for the sole purpose of avoiding being robbed on the street you deserve it. My impression of karate is like yoga. Achieving new levels with your body and mind. There are other ways for self defense and you shouldn't let one incident spoil something that you previously put a lot of effort into.

Im just guessing its wadu ryu style?

The mugger could have had a gun, in which case it wouldn't matter how skilled your instructor is. He was smart to not try to fight because you never know with some random person on the street. Clicking YDI because you're an idiot, OP.

In most countries if you know any form of fighting arts, you are classed as a "human wepon" and can get highly charged for it unless it is equal force. so if this guy didn't lay a hand on him, he can't do anything without being charged for assault. Also doesn't mean he hasn't taught you how to fight/defend yourself, he might just not have the nerve in an actual fight.

That's because he knows karate is worthless in a real fight. I practice ba gua and that is one you should try if you really wanna win a fight...

It was Chuck Norris wasn't it?