Now there is two jackasses causing a disturbance in my movie. Some guy being noisy and another with a bright light from a phone. Sorry, I think your whole premise is flawed.
I, like you, can maybe think of one other bad experience I've had at the movies before this weekend. Tattlr certainly wouldn't be an everyday kind of app. Heck, one may only use it once or twice a year. However, I think there's value in the peace of mind of being in a large dark room knowing a theater attendant is only a couple screen taps away.