Power of Prayer/Meditation

I am facsinated by this. I saw someone post about the movie "What the Bleep is this" so I watched it and they started to get into how a Police cheif in Washington D.C. had 400 people come in from all around the world to meditate to lower crime levels by 25 percent and sure enough it happened. I guess someone else wrote a book about it. Anyway I have always heard of cases of this. So my question is do you believe in this? Do you use it?

Also if bad things start to happen would you do this to protect yourself and people around you?

Also do you feel this can also be used to work in a negative manner?
Not like in the way you hate your neighbor and you want him dead but like if you see someone doing bad and you want it stopped. Like maybe a country leader or a war etc???

Also what would it take for people to use this on a grander scale? How big of an event would have to happen for people to focus in on such things? Most people don't thing about such things unless they have a bad thing happen to their self this is why I ask. What about the world around you?