Never seen a conductor do it, but I've seen other passengers lay into someone for being too rowdy or (especially) talking on the phone. Usually following a comically obvious build-up of red-faced anger over 5-10 minutes or so.
Anecdotally I've heard that social censure is far more common and ruthless in the women's-only cars.
Nah. In Japanese culture, it's simply considered rude to be loud in trains.