UPPER DARBY, Pa. - As police in Upper Darby, Pa., search for more young people involved in last week's flash mob, more adults are thinking about arming themselves with guns. People are talking about how afraid they are of being caught in the path one of these flash mobs while they're out minding their own business, and they want to be ready. Law enforcement officials say it's a nightmare in the making because ordinary, private citizens are getting gun permits. "We have people now that are fearful and carrying guns because of children. How sad is that?" Upper Darby police...