I was in the Heathrow T3 Admirals Club (or Flagship Lounge, don't remember, doesn't matter) a while back when one of these types was having a very loud discussion on his mobile. I wrote a short note and put it in front of him. It said, as best I remember:
You don't know who I am.
You don't know what industry I work in.
You don't know who I know.
He quieted WAY down, REALLY REALLY fast.