I sympathize with how this inconveniences you and you make some excellent points about emergency information being trapped with inside Twitter... but from their perspective you're just not an engaged enough user. You should have your nose in your Twitter stream all the time so you don't miss these kinds of important tweets (or tweets from sponsors about the new Ford Focus).
That people can consume content without consuming it from them is exactly what they want to avoid.
You should have your nose in your Twitter stream all the time so you don't miss these kinds of important tweets
-- Signal to noise ratio. Needed in any emergency.
But this in conflict with Twitter's biz model/direction. That's the problem. This is a negative, step back for a use of the service more valuable to society. The "eyballs" to sell "stuff" biz model is not a great contributor to civiliation. Arguably, twitter has more potential.
That people can consume content without consuming it from them is exactly what they want to avoid.